List of Doctor Who universe creatures and aliens

This is a list of fictional creatures and aliens from the universe of the long-running BBC science fiction television series Doctor Who. The series first aired in 1963 before being cancelled in 1989, with a brief attempt to revive the show in 1996 being unsuccessful. The show was successfully revived in 2005, and continues to air episodes. The series stars an extraterrestrial known as The Doctor who is capable of changing their appearance when they die in a process known as regeneration. They travel through time and space in a machine known as the TARDIS. In the process, the Doctor often comes into contact with various alien species. This list only covers alien races and other fictional creatures and not specific characters. Additionally, several alien races re-appear in Doctor Who 's spin-off series The Sarah Jane Adventures, Torchwood, and Class, though antagonists original to those series do not appear on this list. The separate articles below contain associated lists, which include other similar entities from the series:
 * List of Doctor Who villains
 * List of Doctor Who robots

Abzorbaloff


The Abzorbaloff is an alien creature seen in "Love & Monsters" (2006), that can absorb any living thing into its body by touch. They are from the planet Clom, the twin planet of Raxacoricofallapatorius, the home planet of the Slitheen family. An Abzorbalovian disguised itself as "Victor Kennedy" and infiltrated L.I.N.D.A – a group of people trying to track down The Doctor – although it planned to absorb the Doctor's knowledge. It is killed when Elton Pope, a member of L.I.N.D.A, broke its cane, causing the Earth to absorb it.

The Abzorbaloff was created by nine-year old William Grantham, who won a Blue Peter contest to have a monster created by a child appear on the show. Grantham originally envisioned the Abzorbaloff to be much bigger and fueled by rage, being unable to speak, though he was satisfied with the final version seen on screen. The Abzorbaloff was portrayed on-screen by comedian Peter Kay.

A short direct sequel to "Love & Monsters", titled "The Genuine Article" was released as part of a tie-in with a watch-along for "Love & Monsters" held during the COVID-19 pandemic. The video depicts the Abzorbaloff's father attacking the Tenth Doctor in an attempt to get revenge for the death of his son. The Abzorbaloff summons an alien known as the "Krakanord" to defeat the Doctor, but it kills the Abzorbaloff due to the Abzorbaloff's mistreatment of it. Grantham returned to direct and animate the short, and also judged the monster design competition that created the Krakanord.

Adipose
The Adipose are aliens composed of living fat, featured in the episode "Partners in Crime" (2008). Their breeding world, Adipose 3, was lost, causing them to turn to "Miss Foster" in order to create new Adipose children. She formulated a drug that would cause human fat to morph by parthenogenesis into Adipose children. The process is generally harmless to the host beyond the loss of body fat; but in emergencies the process can be accelerated, converting the host's entire body, which is fatal to the host and produces ill and weak Adipose children. This is illegal under the laws of the Shadow Proclamation, an inter-galactic law body, and the Adipose abandoned Foster to die in order to hide their crimes, taking the infant Adipose with them. In the parallel universe created in "Turn Left" (2008), in which The Doctor is killed fighting another alien menace prior to encountering the Adipose, the Adipose incident happened in America instead of the United Kingdom, as London was destroyed when the space-faring version of the Titanic crashed into Buckingham Palace and caused much of the southern United Kingdom to become an irradiated wasteland. Over 60 million Americans were killed in this timeline as a result.

The Adipose were inspired by a plush toy owned by script writer Russell T Davies, with their name being based on adipose tissue. The Adipose were animated in hordes using Stephen Regelous's software MASSIVE, with Regelous flying to London to aid with coordinating the crowd shots of Adipose. Special effects department The Mill created two types of Adipose for filming. Adipose with artificial intelligence, who independently moved, were used for larger crowd shots, as well as "hero" Adipose, which were animated by hand.

Aggedor
Aggedor is the Sacred Royal Beast of the planet Peladon, first seen in The Curse of Peladon (1972). The real creature upon which the legend is based is a large, hairy beast with a single horn. Hunted to near extinction, one Aggedor beast roamed the tunnels below the citadel and, at one stage, was used to judge prisoners who were cast into a pit to face the Judgement of Aggedor. Peladon's High Priest, Hepesh, secretly captured a remaining Aggedor, and used it to attempt to generate superstition about the "curse" of Aggedor in order to stop Peladon from joining the Galactic Federation, an intergalactic alliance of planets. The Aggedor killed Hepesh, and the same Aggedor later returned in The Monster of Peladon (1974). In both of Aggedor's appearances, Aggedor is portrayed by actor Nick Hobbs.

In the audio story The Bride of Peladon, after the death of the original Aggedor, it was revealed the Aggedor had a child, which remained hidden for many years. The Fifth Doctor mind-controlled this Aggedor to aid them, after which it gave birth to many baby Aggedors.

Axons
The golden-skinned humanoid Axons attempted to take over the Earth by distributing Axonite, actually pieces of a single creature named Axos; they were encountered in The Claws of Axos (1971). They posed as a friendly family who wished to aid humanity, but are able to shapeshift into monstrous forms in order to aid Axos. The Axons were later trapped in a time loop alongside Axos. The Axons are portrayed by Bernard Holley, Patricia Gordino, John Hicks, and Debbie Lee London.

The Axons later re-appeared in the 2010 comic strip "The Golden Ones," published by Panini Publishing. In an attempt by Axos to free itself and resume its feeding following The Claws of Axos, it distributes an energy drink as part of branding for the fictional television show "Goruda," causing the children to become Axons. These Axons begin to rampage across Tokyo until the Eleventh Doctor defeats Axos, which causes the children to return to normal.

Bandril
The Bandrils were a reptilian species encountered in the serial Timelash (1985). A villain known as the Borad sought to start a war between them and the people of Karfel. The Sixth Doctor was able to thwart the plot. The Bandril Ambassador that appears in the episode was portrayed by actor Martin Gower.

Boneless
The Boneless were a group of creatures that hailed from a two-dimensional universe, seen in "Flatline" (2014). The Boneless harnessed the energy from the TARDIS, the Doctor's ship, in an attempt to infiltrate the Doctor's universe. Clara Oswald and a community service worker named Rigsy are able to trick the Boneless into restoring the TARDIS, allowing the Doctor to send them back to their home dimension.

The Boneless later appeared in the comic story The Fourth Wall, published by Titan Comics. The Boneless used comic books to trap readers in their realm. Utilizing a shared mental communication caused by the kidnapped readers' love of comic books, the Twelfth Doctor was able to use the power in the communication to free the readers and send the Boneless back to their home dimension.

Carrionite
The Carrionites are creatures who hail from "The Dark Times," a time before the universe, and fought against the Time Lords in the past. They appear in "The Shakespeare Code" (2007). Three Carrionites- Bloodtide, Doomfinger, and Lilith- attempt to release their species from a prison using the power of words and witchcraft. They attempt to manipulate William Shakespeare into writing the key to their escape into Love's Labour's Won, but the Tenth Doctor and Shakespeare were able to reverse the process, sending the Carrionites back into their prison and trapping Lilith, Bloodtide, and Doomfinger into a crystal ball. They reappeared, this time facing against the Sixth Doctor, in the audio drama The Carrionite Curse.

Catkind
The Catkind are felines in the future that have evolved into humanoids, first seen in "New Earth" (2006). The Catkind have hair-covered bodies, feline facial features and retractable claws. Their young resemble typical domestic kittens, with humanoid features emerging after ten months.

In "New Earth", a group of Catkind called the Sisters of Plenitude ran a hospital near the city of New New York, where they tested on human subjects by infecting them with every disease in order to concoct cures for them. The subjects later escaped, infecting many in the hospital, including several of the Sisters. The Tenth Doctor later developed a cure for the infected, and the Sisters are arrested. In "Gridlock" (2007), most of New New York is killed by a plague, leaving the only survivors in the Under City and Motorway. A Cat Person, Thomas Kincade Brannigan, is encountered by the Tenth Doctor, and has a human wife and a litter of kittens. Additionally, a surviving member of the Sisters of Plentitude, Novice Hame, appears, who survived the plague via the protection of The Face of Boe. She aids the Tenth Doctor in opening the Motorway. Hame was portrayed by actress Anna Hope. Brannigan has several kitten offspring who appear in "Gridlock," who were portrayed by real-life kittens.

A short scene, titled "The Secret of Novice Hame" was released as part of a tie-in with a watch-along for "New Earth" held during the COVID-19 pandemic. The scene features Hame on her deathbed in the far future as she awaits the Doctor's arrival.

Chameleons
Chameleons are aliens with no features or identities of their own seen in The Faceless Ones (1967), who can imprint on individual humans and take on their appearance. The Chameleons lost their identities and faces in a massive explosion on their home planet. As a result, their scientists created a device that would allow them to adopt the identities of other beings. In the late 1960s, they ran a fake airline, Chameleon Tours, to kidnap human subjects for that purpose. The Second Doctor was able to convince them to seek another solution. The Chameleons later re-appeared in the spin-off book Short Trips and Side Steps, appearing in a short story in the book titled Face Value. In the story, the Chameleons began to infiltrate and replace the people of the planet Krennos after their last defeat by the Second Doctor. The Sixth Doctor discovered their plan and put a stop to it.

Cheetah People
Cheetah People are feline humanoids greatly resembling cheetahs who enjoy hunting humans; the Doctor and the Master encountered them in Survival (1989). The Cheetah People were once humanoids resembling humans, but they made bonds with cat-like creatures known as Kitlings, which caused the people to mutate into more wild creatures. The Cheetah People frequently fought each other, which weakened their home planet and caused it to slowly reach a breaking point. The Master became stranded on the planet, and slowly began to mutate as well. He attempted to use the Cheetah People to escape, kidnapping several of Ace's friends and mutating them into Cheetah People. The Seventh Doctor was able to stop the Master, leaving him stranded on the Cheetah People's dying planet.

The writer of Survival, Rona Munro, was disappointed with how the Cheetah People turned out. Her initial outline only had the Cheetah People have cheetah-like eyes and a pigmentation of the skin, but the final version depicted the Cheetah People with heavy masks that obscured the actors' faces, which Munro weakened the emotions the actors were able to convey, and which she believed particularly weakened the lesbian subtext between Ace and one of the Cheetah People.

Chronovores
Chronovores are glowing white creatures that live outside time; the Doctor encountered one, Kronos, in The Time Monster (1972). The Master attempted to use Kronos for one of his schemes, infiltrating the lost kingdom of Atlantis, which worshipped Kronos, in order to revive and control the deity. After Kronos destroyed Atlantis, the Third Doctor was able to free Kronos, thwarting the Master's plans.

The Chronovores re-appeared in the book The Quantum Archangel, in which Kronos sought revenge against the Master and tricked him into cutting off a point in the dimensions known as the Lux Aeterna. This created the Quantum Archangel, which, in order to satisfy the desires of every human on Earth, created seven billion alternate realities. The Chronovores swarmed the planet and began to feed on the Earth, acting like parasites to prolong their meal. Kronos sacrificed itself in order to stop this, freeing the Lux Aeterna and causing the Chronovores to return to their dimension.

Chuldur
The Chuldur are a race of shape shifting bird-like aliens who appeared in the Fifteenth Doctor story "Rogue" (2024). The Chuldur appeared in 1813, where they infiltrated a ball in order to "cosplay" as those from the nineteenth century. The Fifteenth Doctor is able to trap the Chuldur within a sealing device, which banished them to another dimension, but at the sacrifice of Rogue, a bounty hunter the Doctor had fallen in love with.

Cryons
Cryons are a species of alien first seen in Attack of the Cybermen (1985). Cryons appear to be an all female race who cannot exist at temperatures above zero degrees. The Cryons lived on Telos until the Cybermen took control of the planet, and allied with the mercenary Lytton in order to defeat them. The Cryons were later destroyed by an attack by the Cybermen. Director Matthew Robinson elected to make the Cryons an all-female race, as otherwise Attack of the Cybermen would have had an all-male cast barring the Sixth Doctor's companion Peri Brown. Sarah Berger, Esther Frued, Faith Brown, and Sarah Greene all portrayed various Cryons in the episode.

Cyberman
The original Cybermen were a race of humanoids originating on Earth's twin planet Mondas, first seen in The Tenth Planet (1966). As they implanted more and more artificial parts into their bodies as a means of self-preservation, they became coldly logical and calculating, with emotion all but deleted from their minds. The Cyberman concept was created by Dr. Kit Pedler (the unofficial scientific advisor to the programme) and Gerry Davis in 1966, based around the ideas of the ethical issues present in innovations in prosthesis. The Cybermen were portrayed by tall actors in order to portray the Cybermen's menace, with the actors being over six feet in height. The costumes were hot and bulky, and it was difficult for the actors to see. These initial Cybermen used cloth masks, and had a zombie-like appearance, with flesh-based hands. They additionally had individual names. The Cybermen were brought back as recurring antagonists in other serials following this, and were an effort by the production team to find replacement antagonists due to the Daleks being planned to be featured in an American television series at the time. The Cybermen's design would change frequently from episode to episode, and grew more mechanical and bulky in design. Despite their popularity, the Cybermen were not brought back for any episode starring Jon Pertwee as the Third Doctor, and only had one appearance alongside Tom Baker as the Fourth Doctor. Producer John Nathan-Turner brought the Cybermen back for the serial Earthshock (1982), wanting to feature a returning antagonist but not wanting to use the Daleks. Turner kept the reveal of the Cybermen a secret from the public prior to the airing of the episode, after which they reprised their role as consistent antagonists until the series' cancellation in 1989.

In the two-part story "Rise of the Cybermen" and "The Age of Steel" of the second revived series (2006), the Cybermen originate on a parallel-universe version of Earth, where they were created by John Lumic, the head of "Cybus," who was a genius obsessed with immortality. He forcibly 'upgraded' vast numbers of people in the parallel earth before a counter-revolution, initiated by the Tenth Doctor, started fighting back. These Cybermen acted as recurring foes, aiming to "upgrade" other life-forms to be like themselves, but after Steven Moffat took over as the showrunner of Doctor Who, the Cybermen from the Doctor's universe became the primary antagonists, though they still used the design of the "Cybus" Cybermen. The Cybermen were later re-designed for writer Neil Gaiman's serial "Nightmare in Silver" (2013) which used a sleeker design. These Cybermen were constantly upgrading to counter-act any threat, which Gaiman cited as being inspired by the speed of improvement in modern technology and the Cybermen's own penchant to "upgrade" other lifeforms to be like themselves. The original design seen in The Tenth Planet was later brought back for "World Enough and Time" and "The Doctor Falls" (2017), while the main Cyberman design was redesigned again for the episode "Ascension of the Cybermen" (2020).

The Cybermen have several variants, such as the Cybermat, small cybernetic creatures used by the Cybermen first seen in The Tomb of the Cybermen and the Cybershades, a sub-species of Cybermen, seen in the 2008 Christmas special, "The Next Doctor".

Dæmon
A race of humanoids from the planet Dæmos, seen in The Dæmons (1971). They resemble demons, and inspired the concept of demons in humanity. The Dæmons have great power, and the antagonist the Master attempts to obtain the power of a Dæmon named Azal. Azal is the last of his kind, and eventually decides to give his power to the Master as he threatens to kill the Third Doctor. The Doctor's companion, Jo Grant, steps in the way in an act of self-sacrifice. This confuses Azal due to its illogical nature, causing his powers to reverse on him, killing him.

Another Dæmon later appeared in the unofficial 2004 BBV film Dæmos Rising, which acted as a follow-up to The Dæmons. The same Dæmon later appeared in the spin-off novel Child of Time, where it attempted to harness the powers of a woman named Maria. Maria travelled back in time and committed suicide, thwarting its plans and causing it to be killed.

Dalek
The Daleks are a warmongering, xenophobic race of mutant creatures who live within mobile battle armor first appearing in The Daleks (1963-64), the second Doctor Who serial. The Daleks were created by a scientist named Davros as a way to survive and win a war between themselves and a species known as the Thals. They are life-long enemies of The Doctor, and he is the only being whom they fear. The Daleks see themselves as the superior lifeforms in the universe, and seek to eliminate all other life for being "impure." The creatures inside of their casings resemble squids, with a single eye, exposed brain and many tentacles. The Daleks acted as a highly recurring foe during Doctor Who 's classic era, and were among its most popular. During the 1960s, public popularity for the Daleks was high, with this era being referred to as "Dalekmania." Despite The Beatles going on-air during the Daleks' second appearance, the return of the Daleks saw a higher viewer count. The Daleks were merchandised heavily during this period and grew wildly popular. Dalekmania declined following the airing of The Daleks' Master Plan, a twelve part serial. Two movie spin-offs of Dalek serials, starring actor Peter Cushing as the Doctor, titled Dr. Who and the Daleks and Daleks' Invasion Earth 2150 A.D., were adaptations of other Dalek serials and produced at the highlight of Dalekmania.

The Daleks were created by Terry Nation and designed by the BBC designer Raymond Cusick. Nation's design inspiration for the Daleks came from watching a dance troupe on television, as their long skirts gave the impression that they glided across the stage. Nation additionally pulled from the cultural memory of World War II and the Nazis in designing the Daleks, and acted as an allegory for the Nazis. Cusick was only given an hour to work on the design for the Daleks, and was inspired by a pepper pot on the table. The in-human aspects of the design were considered a large part of what made the Daleks a success.

The Daleks use physical props, which are operated from the inside by actors, who manipulated aspects such as the eyestalks and appendages, and physically moved the props. For the 2019 episode "Resolution," a fully remote controlled prop was created for the Dalek. Notable Dalek operators include John Scott Martin, Barnaby Edwards, Nicholas Pegg, Jon Davey, Tony Starr, and Cy Town. Several variant designs for the Daleks existed throughout the series, including a variant known as the "Special Weapons Dalek."

The Daleks' voice has a harsh, staccato delivery. Actors Peter Hawkins and David Graham designed the voices for the Daleks and voiced them, with the voices further processed by Brian Hodgson in the BBC Radiophonic Workshop. Other actors to portray the Daleks include Roy Skelton and Nicholas Briggs, the latter of whom voices the Daleks in the revived series. Briggs uses a voice modulator to perform the Daleks, and had previously performed as the Daleks in the Big Finish Productions audio dramas featuring them.

Upon the airing of The Daleks, Nation received large amounts of letters from children who watched the series, inquiring about the Daleks. The popularity of the Daleks ensured the survival of Doctor Who, which was in danger of being cancelled due to low viewing figures from the prior serial, An Unearthly Child (1963). The ownership of the Daleks was a co-production between Nation and the BBC, and as a result, Nation received royalties whenever the Daleks appeared in Doctor Who. The Daleks have been described as British cultural icons, and a 2008 survey stated that nine out of ten British children were able to identify a Dalek correctly. The word "Dalek" has entered dictionaries, including the Oxford English Dictionary.

In the series' revival in 2005, the Daleks were initially not going to appear, with drafts of the scripts not featuring them being made if the development team was unable to use them. This was due to issues in negotiations with Nation's estate after his death in 1997, with the estate not trusting the BBC with the Daleks and the BBC not offering the same editorial control Nation had once had in the past. The BBC and Nation estate eventually came to an agreement, leading to the return of the Daleks in the episode "Dalek" (2005).

In the revived series, the Daleks fought the Doctor's species, the Time Lords, in a conflict known as the Time War, which resulted in the destruction of the Daleks and the Time Lords alike, with the Doctor the sole survivor. The Doctor eventually comes into contact with Dalek survivors as the series progresses, and the Daleks are eventually revived in the episode "Victory of the Daleks" (2010). The Daleks have since gone on to be recurring antagonists in the series.

The Daleks were briefly re-designed following "Victory of the Daleks," gaining six roles with multiple colors. Writer Mark Gatiss was inspired by the Daleks seen in the 60s Dalek films, and sought to make them big to make them intimidating. A green Dalek was planned but scrapped. These Daleks, dubbed the "New Paradigm," were widely controversial with viewers. They were re-designed for the episode "Asylum of the Daleks," (2012) but did not re-appear in subsequent episodes.

Dominator
The Dominators are a race of aggressive warlords, first seen in The Dominators (1968). They attempted to capture the planet Dulkis utilizing their robotic servants the Quarks, but were thwarted by the Second Doctor.

The Dominators later appeared in various pieces of spin-off material. The comic Quiet on the Set, released in 2013 by IDW Publishing, depicted the Tenth Doctor fighting the Dominators in Hollywood, Los Angeles, where they attempted to make a movie that would spread subliminal messaging to turn humanity into an ideal labor force for them. They re-appeared in the novel Mutually Assured Domination, published in 2015, where they set up the company Dominex Industries in order to harness nuclear waste to power their fleets, only to be defeated by Brigadier Lethbridge-Stewart. The audio drama Time in Office later depicted the Dominators attempting to conquer the Doctor's home planet of Gallifrey, though they were thwarted.

Draconian
The Draconians (also called Dragons, a derogatory term in their culture) are a humanoid race seen in Frontier in Space (1973). Common interstellar travel and attempts at colonization have brought them into frequent and occasionally hostile contact with humans, leading to a treaty establishing a frontier between the two empires. Antagonist the Master attempted to trick the two sides into thinking the other broke the treaty in order to provoke galactic war, but after the truth was revealed, the Draconians allied with the humans to combat the Master.

The Draconians appear in several pieces of spin-off material. The 2020 online short story The Simple Things depicted a Draconian attempting to repair a battle cruiser in 1896 West Ham with the help of an ironworks company. The 1998 novel Catastrophea depicted the Draconians being unhappy with human colonization of the planet Catastrophea. They attempted to intervene, but after an uprising by the planet's natives, the Draconians and humans work together to make sure all inhabitants from both sides are able to evacuate the planet, with both choosing to leave the planet alone. The 2009 comic story Fugitive featured a Draconian delegate, who was arrested alongside the Tenth Doctor and delegates from the Ogron and Sontaran species. The Draconian delegate later aided the Tenth Doctor in saving the Shadow Architect, head of the Shadow Proclamation, an intergalactic police body who had arrested them before. The Draconian was freed and later attended peace talks with the other delegates.

Drahvin
The Drahvin are a group of aggressive female aliens first seen in Galaxy 4 (1965). In the serial, a group of Drahvin were stranded on a planet that was soon to die. They were trapped with the Rills, a physically repulsive race, who offered aid but were rejected. The Drahvin attempted to kill the Rills, but were stopped from doing so by the First Doctor, and were killed when the planet was destroyed.

The Drahvin appeared in the 2010 spin-off audio drama The Suffering, which detailed the Drahvin's past. The Drahvin were once ruled by a patriarchal shared mind, with one female Drahvin being able to allow other female Drahvin to enter the mind. The Drahvin was killed, but her shared connection to the female Drahvin let her overthrow the patriarchy and institute a matriarchy. Following her tyrannical rule over the Drahvin, she was deposed and her body was sent into space. In the audio drama, the Drahvin attempted to cause an uprising at a suffragette rally, but was stopped by the First Doctor and his companions.

Drashig
Drashigs are huge, aggressive and hungry creatures with caterpillar bodies and dragon heads, seen in Carnival of Monsters (1973). In the serial, the Drashigs were captured inside a "Miniscope," a device which kept various species trapped in miniature versions of their natural environments for entertainment. The Drashigs damage the circuitry of the Miniscope, while a group known as the Tribunal attempts to free them to cause chaos. The Drashigs kill the rogue Tribunal members, and are returned home from the Miniscope at the episode's conclusion. The Drashigs in this episode utilized puppets, with fox skulls being used for the heads. The documentary Destroy All Monsters!, released as part of the 2011 DVD release of Carnival of Monsters, detailed several aspects of the Drashigs' production. The Drashigs' name was an anagram of "dish rag" due to dish rags being used as an eyeline for the actors when filming scenes in which they encountered Drashigs. The Drashigs' roars were created by reversing the sound of a car tire screeching backwards.

Drashigs re-appear in spin-off material for the series. The Drashigs, still trapped in the Miniscope following Carnival of Monsters, re-appeared in the 2019 audio drama Peepshow, where recurring character River Song encountered them. Due to the lack of food in the Miniscope, she was able to use the Drashigs to kill several antagonist groups in the Miniscope trying to kill her. The Third Doctor returned the Drashigs to their home at the end of the audio drama. The Faction Paradox short-story anthology, The Book of Peace, released in 2018, depicted the Drashigs' creation in the short story Daring Initiation. The Drashigs in this story were the result of genetic mutation in humans who were exposed to radiation when stranded on an alien planet. Some of these mutated humans' eggs were sent back in time, creating the Drashigs. The book The Eight Doctors, published in 1997, depicted a Drashig being pulled through time via a device known as a Time Scoop. The Drashig was sent to kill the Fifth and Eighth Doctors, but the pair reversed the Scoop, sending the Drashig to kill the one who initially used the Scoop. Another audio drama, titled Planet of the Drashigs, was also released in 2019. The Fourth Doctor encountered them on a planetoid known as "DrashigWorld," a theme park where various species of Drashig are on display. The creator of the park attempted to use it as a ploy to discover what it is like to be a Drashig by connecting to the Drashigs' brain waves. The Drashigs break free, but the Doctor is able to evacuate the survivors before the Drashigs are able to kill everyone.

Eknodine
The Eknodine are a parasitic life form seen in "Amy's Choice" (2010). In the dream world created by the Dream Lord, the Eknodine reside in the bodies of elderly residents in Leadworth. The Eknodine attack the Eleventh Doctor, Amy Pond, and Rory Williams, killing the latter, before Amy kills both her and the Doctor in the dream world, ending the threat of the Eknodine.

Eternals
The Eternals are a race of cosmic beings first introduced in Enlightenment (1983). The Eternals live outside of time, in the realm of eternity. They consider the mortal inhabitants of the universe to be "Ephemerals." The Eternals are powerful enough to manipulate matter, creating objects out of thin air; they also read minds effortlessly through telepathy. They lack imagination and creativity, stating that they were empty and lost without Ephemeral thought to entertain and challenge them.

In Enlightenment, the Fifth Doctor ended up encountering a group of Eternals, who sought to win the "Enlightenment" from the Black and White Guardians in a competition between themselves. The Eternals captured many residents of the universe to participate in the competition, with the Doctor attempting to stop the competition. An Eternal naming themselves Captain Wrack is able to pull ahead in the competition, which involves many spaceships based off boats racing to see who would make it to victory. A rival ship, the Buccaneer, allied with the Doctor to stop Wrack from winning, with the Doctor killing her and her first mate, allowing him to win the race and stop the Eternals from claiming Enlightenment.

Though the Eternals were referenced in the revived series, they did not re-appear physically until "Can You Hear Me?" (2020), in which a pair named Zellin and Rakaya appear as the primary antagonists. Rakaya was imprisoned for causing chaos, and Zellin manipulated the Thirteenth Doctor so that she would free Rakaya. The pair wished to siphon nightmares in order to feed on them. The Doctor is able to trick the pair, imprisoning them once again.

Fendahl
The Fendahl are an alien species seen in Image of the Fendahl (1977). A race that never exceeds unlucky number 13; it is composed of one Golden Core and 12 Fendahleen. The Fendahl arose on the original fifth planet of our solar system, which they eventually wiped of all other life; so dangerous were they that the Time Lords moved the planet into a time loop. Somehow, though, the Fendahl managed to eject a skull, which passed through space (seriously harming life on Mars as it passed) to land on Earth, where its powers helped shape humanity, a new vessel for the Fendahl. Ages later, that skull was found by scientists, who believed it could grant them power; the attempt unfortunately backfired in the creation of a new Golden Core. The Core began creating Fendahleen, but one person committed suicide, preventing the Fendahl from reaching the quota. The Fourth Doctor blew up the house the Fendahl were in, and later tossed the skull that caused the trouble into a supernova.

Fish People
Fish People are humanoids from Atlantis who have been surgically altered to live underwater; they appear in The Underwater Menace (1967). The Fish People were subsequently convinced to strike against the villainous Professor Zaroff, joining the rebellion against him.

Foamasi
The Foamasi are an intelligent, bipedal race of reptiles who appeared in The Leisure Hive (1980). The Foamasi fought a twenty minute nuclear war with the Argolins, which resulted in the decimation of their planet, Argolis. Argolis subsequently came under the Foamasi's control. Two saboteurs, hailing from a group known as the "West Lodge" attempted to force the Argolins to sell the Leisure Hive, a location within which the Argolins survived. The saboteurs were thwarted and subsequently arrested by the Foamasi government. The Foamasi that appeared in the episode was portrayed by actor Andrew Lane.

The 1998 novel Placebo Effect depicted another group of Foamasi, known as the Dark Peaks Lodge, attempting to sabotage and gain control of the Foamasi government. The Eighth Doctor was able to reveal the group, causing the Foamasi government to hunt down the Dark Peaks Lodge.

Futurekind
The Futurekind are a cannibalistic humanoid species that live at the end of the universe, seen in "Utopia" (2007). With sharp teeth and warrior-like markings and piercings over their faces, the Futurekind are tribalistic, and hunt down those they can kill and eat. The Futurekind attempted to kill the Tenth Doctor and his companions when they wound up at the end of the universe, and later broke into the last human sanctuary when The Master let them in. The Doctor was able to use a vortex manipulator, a device that can allow the wearer to travel through time, to get him and his companions to safety.

The Flood
The Flood is a viral entity resembling water found on Mars, appearing in the special "The Waters of Mars" (2009). The Tenth Doctor speculates that they may have been imprisoned by the Ice Warriors within a glacier. The Mars base Bowie Base One utilizes the glacier for water, but when one of their water filters breaks the Flood begins to infect the personnel, transforming them into a zombie like state that can produce the infectious water, with unusual electrical activity in the brain and blackened teeth. As the Flood overrun the base with the intent of reaching Earth the Doctor decides he must leave, knowing that the base's destruction is a fixed point in time that can't be changed. He soon returns but the base's leader, Adelaide Brooke, activates the base's self destruct feature. Arrogantly breaking the laws of time, the Doctor manages to save the remaining crew not infected by the water and the Flood is destroyed with the base.

Gelth
The Gelth were blue gaseous life-forms that appeared in "The Unquiet Dead" (2005). The Gelth claimed to have lost their corporeal forms as a result of the Last Great Time War, and possessed human cadavers in Victorian England in order to have hosts, though the cadavers did not last long. The Gelth spoke through a maid named Gwyneth, and asked for Gwyneth to use her abilities to open the Cardiff Rift in order to let the Gelth through to possess corpses, which the Ninth Doctor believed would allow him to find the Gelth new bodies. However, once the Rift was open, the Gelth revealed their malicious intent and threatened to take Earth by force. Gwyneth sacrificed herself to close the Rift, setting the remaining Gelth ablaze with fire.

Graske
The Graske are a race of diminutive aliens that first appeared in the interactive Doctor Who mini-episode "Attack of the Graske" (2005). They infiltrate planets by subtly replacing members of the planet's species with disguised Graske.

A Graske named Krislok appears in The Sarah Jane Adventures stories "Whatever Happened to Sarah Jane?" (2007) and "The Temptation of Sarah Jane Smith" (2008). Originally a henchman and slave of the Trickster, who saved him from death, Krislok later gains his freedom. An unnamed Graske appears in The Proms mini-episode "Music of the Spheres" (2008). A similar species known as the Groske appeared in The Sarah Jane Adventures episode "Death of the Doctor".

The Graske has been portrayed by actor Jimmy Vee.

Great Intelligence
The Great Intelligence is a creature with no physical form of its own, which first appeared in The Abominable Snowmen (1967). It returned in the serial The Web of Fear (1968) and did not re-appear until the episode "The Snowmen" (2012). The Intelligence later orchestrated events to force the Doctor to the planet of Trenzalore in "The Name of the Doctor" (2013) so that the Intelligence could access the Doctor's time stream and undo all of the Intelligence's past defeats. The Intelligence is thwarted by Clara Oswald, who jumps into the Doctor's time stream and splits into copies of herself, with each stopping the Intelligence's interference in the Doctor's timeline.

The Intelligence has several servants it uses to aid in its plans. The first are the Yeti, who appear in The Abominable Snowmen and The Web of Fear. Another Yeti later appeared in "The Five Doctors." The Yeti were an effort of the production team to find recurring antagonists to replace the Daleks, who at the time were written out of the series. The Snowmen appeared in "The Snowmen," where they were sentient snow that manifested when people thought about them. The Snowmen were defeated alongside the Intelligence. The Whisper Men were servants of the Intelligence who appeared in "The Name of the Doctor" (2013). Their hands can phase through a person's chest and stop their hearts at will. The Whisper Men capture the Doctor's friends the Paternoster Gang, forcing the Doctor to Trenzalore in order to face the Great Intelligence.

Goblins
The Goblins are a group of time-travelling creatures. They are attracted by coincidence and feed on infants as a food source. The Goblins appeared in the 2023 Christmas special "The Church on Ruby Road" where they attempted to capture a baby being fostered by Ruby Sunday's mother, Carla Sunday, and feed it to their King. Ruby and the Fifteenth Doctor are able to save the baby, but the Goblins go back in time to steal Ruby when she was a baby. Using special gloves that enhance his strength, the Fifteenth Doctor drags the Goblins' ship into the steeple of a church, impaling their King and saving Ruby. A scrapped scene in the episode would have had Ruby fight the Goblin King using luck from scratchcards, but this was scrapped for budgetary reasons.

One Goblin, named Janis Goblin, sang a song in the episode named "The Goblin Song," which was performed by Christina Rotondo. The song was composed by series composer Murray Gold and released as a single.

Guardians
The Guardians are a pair of powerful entities in charge of keeping balance in the universe, first seen in The Ribos Operation (1978), where the White Guardian appeared before the Doctor and asked him to re-assemble The Key to Time, warning them of the Black Guardian who also wished to obtain the Key. The White Guardian was later revealed to actually be the Black Guardian in disguise, who attempted to trick the Doctor into assembling the Key for him. The Doctor scrambled the TARDIS's piloting abilities, causing the TARDIS's landing sites to be randomized in order to evade the vengeful Black Guardian. The Black Guardian later appeared in several episodes of the series, where he attempted to manipulate Vislor Turlough into killing the Fifth Doctor. Both Guardians later appeared in Enlightenment, where the Guardians offered a crystal of great power to the winner of a race held by Eternals. Turlough threw the crystal at the Black Guardian, causing him to dissipate. The White Guardian was portrayed by actor Cyril Luckham, and briefly by Valentine Dyall in The Armageddon Factor. Dyall portrayed the Black Guardian in the character's later appearances.

Haemovore
Haemovores appeared in the Seventh Doctor story The Curse of Fenric (1989). Vampiric creatures that fed on blood, they were the result of human evolution in a possible far future, caused by millennia of pollution. As part of his final game against the Doctor, the entity known as Fenric transported the most powerful Haemovore, called the "Ancient One", through time to Viking Age Northumbria. There it waited, trapped beneath the North Sea for centuries, occasionally drawing victims into the water and transforming them into Haemovores.

Soon after the transformation, victims appeared much as they did in life, except for elongated fingernails and a corpse-like pallor. Later they became deformed blue-grey humanoids covered in octopus-like suckers. The Ancient One was the least human in appearance; in its own time, it was the last living thing on Earth.

During World War II, Fenric released the Ancient One. Fenric's plan was that the Ancient One was to release the toxin which would pollute the world and thus create its own future.

The Haemovores had the ability to hypnotically paralyse their victims so they could feed and drain them of blood. Not all of their victims were turned into Haemovores, although the selection process was never explained. The Haemovores were impervious to most forms of attack, surviving being shot at close range by a submachine gun at one point. They could be destroyed in the traditional vampire-killing fashion of driving a stake through their chests. They could also be repelled by their victim's faith, which formed a psychic barrier, like the Doctor's faith in his companions, Ace's faith in the Doctor, Captain Sorin's faith in the Communist Revolution, and the Reverend Wainwright's faith in God; this repelling force can be called into will, the Doctor merely called the names of past companions as a medium.

Ultimately, the Seventh Doctor convinced the Ancient One to turn against Fenric, and it released the toxin within a sealed chamber, destroying itself and Fenric's host. Whether this means that the future the Ancient One came from was averted is not clear, although the Doctor seemed to think so.

Fenric and his Haemovores return in the 2012 Big Finish Productions audio story, Gods and Monsters.

Hath


The Hath are aliens that appear in "The Doctor's Daughter" (2008). They appear as tall, roughly humanoid creatures with fish-like heads, who can breathe in air via the employment of apparatus fitted to their faces that incorporates a canister of green liquid. They are intelligent, emotional creatures – one formed a friendship with Martha Jones, and saved her life at the cost of its own. They seem sentient and while they do not speak a language intelligible to humans, the two races planned to colonize the planet Messaline together. However, they later turned on each other – before their eventual reconciliation, thanks to the Doctor's intervention.

Headless Monks
The Headless Monks are a religious order that can be converted from any humanoid species by the removal of the head, who first appeared in "A Good Man Goes to War" (2011). They wear hooded cloaks, giving the impression that they still have a head, however under the hood, the skin is tied into a tight knot where the head has been removed. Despite their name, most people are unaware of this literal description being true, because except under very special circumstances, one incurs a death penalty if they ever remove the hood of a monk. The monks have no detectable life signs, and are endowed with the ability to throw lightning from their hands. They were first mentioned in "The Time of Angels" (2010), but did not appear until "A Good Man Goes To War" in 2011.

Hoix
The Hoix first appeared in the episode "Love & Monsters", where the Tenth Doctor and his companion Rose Tyler attempt to stop one, during which they are briefly encountered by the episode's protagonist, Elton Pope. A Hoix later appears in the series Torchwood in the episode "Exit Wounds" (2008). One of the protagonists, Owen, distracts it by feeding it cigarettes stating that it "lives to eat". One appeared as a member of an Alliance to seal the Eleventh Doctor inside of the Pandorica, a specially-made prison for the Doctor, in "The Pandorica Opens" (2010).

Ice Warrior
Ice Warriors are reptilian humanoids from Mars that first appeared in The Ice Warriors (1967). The Ice Warriors wore bulky armor, which protects them from temperature fluctuations and enemy attack. They can additionally attack using sonic weaponry. Ice Warriors can remove their armor. The Ice Warriors initially intend to find a new world due to Mars being uninhabitable via conquest, but their re-appearances in the serials The Curse of Peladon and The Monster of Peladon portrayed them as having shifted towards peace, though a group in the latter episode had not eschewed violence. The Ice Warriors later re-appeared in the episodes "Cold War" and "Empress of Mars." The Ice Warriors followed a code of honor, which they treated very seriously. The Ice Warriors have a leadership ranking, being led by Ice Lords, which wear differently designed armor. They are additionally led by a Queen, who was portrayed by actress Adele Lynch.

Following The Evil of the Daleks, the Doctor Who production team wished to introduce new recurring monsters to replace the Daleks, who were planned to be featured in an American television series at the time. The Ice Warriors were created by writer Brian Hayles, who penned every episode featuring them in the classic era of the show. Hayles was inspired by the discovery of a pre-historic mammoth to write the original serial. Hayles initially proposed the Ice Warriors to have cybernetic enhancements, which was scrapped by costume designer Martin Baugh out of concerns that it would be seen as too similar to the Cybermen. They were designed to be able to show more personality than other recurring monsters, such as the Daleks and Cybermen. Baugh additionally gave the Warriors their reptilian appearance when designing them, with two different suits for the Ice Warriors being produced for their debut serial. Baugh designed the armor out of fibreglass. The armor was later given a redesign for their appearance in "Cold War," though it kept the basic design mostly the same. Neill Gorton, a creature designer for Doctor Who, chose to make the redesign resemble plating in order to make the Ice Warriors appear "beefier and stronger." Urethane rubber was used for the costume instead of fibreglass like their older costumes. Gorton sought to improve on the armor due to shortcomings in the older models, with the armor being specially designed around Spencer Wilding, who portrayed the Ice Warrior Grand Marshal Skaldak in "Cold War."

The Ice Warriors proved to be popular, and they were thus brought back in later episodes. Bernard Bresslaw portrayed the Ice Warrior Varga in their debut serial. Bresslaw voiced Varga with a notable whisper-like to depict the Ice Warriors' reptilian nature, with the voice believed to have been developed by Bresslaw. Steve Peters, Tony Harwood, and Sonny Caldinez portray them in the serial The Seeds of Death.

Judoon


The Judoon are a galactic alien police resembling rhinoceroses, who recur throughout the series. They first appeared in "Smith and Jones" (2007), where they sought to capture an alien fugitive by transporting an Earth hospital onto the Moon. They later re-appeared in "The Stolen Earth" (2008) where they aid The Shadow Proclomation, an inter-galactic body of law, and later made cameo appearances in other episodes of the series. They also appeared in the series 3 Sarah Jane Adventures story, "Prisoner of the Judoon" (2009), where a Judoon captain is in pursuit of an escaped prisoner known as Androvax.

The Judoon are blunt in their applications of laws, with the Tenth Doctor describing the Judoon as "interplanetary thugs" due to their methods. The Judoon use energy weapons to incarcerate prisoners, and can breathe for some time in space due to their powerful lungs.

The Judoon appeared in the series 12 episode "Fugitive of the Judoon" (2020), where they attempt to find and arrest The Fugitive Doctor, who is hiding out in Gloucester. The Judoon captain in the episode is named Pol-Kon-Don, named after the Doctor Who fan Paul Condon, who passed away a year before the episode released. The Judoon re-appear in the finale episode "The Timeless Children" (2020) where their "cold case unit" appears and imprisons the Thirteenth Doctor at the end of the episode.

Kahler
The Kahler are a highly technologically advanced humanoid species encountered in "A Town Called Mercy" (2012). They have unique patterns on the left side of their faces to reflect their individuality. A Kahler doctor, Kahler-Jex, encountered the Eleventh Doctor, Amy Pond and Rory Williams in a small American frontier town known as Mercy, where it became apparent that he was responsible for the creation of a deadly Kahler cyborg, who was now hunting him down to execute Kahler-Jex for his crimes against the Kahler species. The Kahler race were created by Toby Whithouse.

Kraal
The Fourth Doctor and Sarah oppose the Kraals in the 1975 serial The Android Invasion, when the creatures attempt to take over the Earth using robot duplicates of key people in UNIT.

The Kraals reappear in a Big Finish story called The Oseidon Adventure, which was released in June 2012 as part of the Fourth Doctor Adventures.

Krafayis
The Krafayis appear in the episode "Vincent and the Doctor" (2010). It appears to be invisible to most people, however Vincent van Gogh can see it. It is suggested that this is because of his mental illness.

Krargs
Krargs appear in the unfinished serial Shada (1979/1980) and consequently in its later Big Finish/BBCi remake. They are artificial crystalline organisms with rudimentary mobility and understanding of simple commands, created and controlled by the main antagonist, Skagra, to aid in his plan to forcefully merge all of the minds in the Universe into a single omnipotent entity.

Krillitane
The Krillitanes are a race who take attributes from other races to change their appearance. In the episode "School Reunion" (2006), the Tenth Doctor states that he has encountered them before, but that due to their composite nature, they looked different, hence him not recognizing them. He also states that they gain their composite nature from consuming other beings.

Kroton
The Krotons are a crystalline species encountered in The Krotons (1968-69).

Krynoid
The Krynoids appeared in the Fourth Doctor story The Seeds of Doom (1976). They are a highly dangerous, sentient form of plant life which are renowned amongst galactic botanists. They spread via seed pods which travel in pairs and are violently hurled through space by frequent volcanic eruptions on their unnamed home planet. The pods when opened are attracted to flesh and are able to infect and mingle their DNA with that of the host, taking over their body and slowly transforming them into a Krynoid. The species can also exert a form of telepathic control over other plant life in the surrounding area, making it suddenly dangerous and deadly to animal-kind. In the later stages of development the Krynoid can also control the vocal cords of its victims and can make itself telepathically sympathetic to humans. Fully grown Krynoids are many meters high and can then release hordes of seed pairs for further colonisation.

Two pods arrived on Earth at the South Pole during the prehistoric Pleistocene era and remained dormant in Antarctica until discovered at the end of the twentieth century. One of them hatched after being exposed to ultra-violet light, and took control of a nearby human scientist. The Fourth Doctor intervened in the nick of time and ensured the Krynoid was destroyed by a bomb, but the second pod was stolen and taken to the home of millionaire botanist Harrison Chase in England. Chase ensured the germination of the second pod, which overtook his scientific adviser Arnold Keeler, and transformed its subject over time into a virtually full-sized Krynoid. Unable to destroy the creature by other means, and with the danger of a seed release imminent from the massive plant, the Doctor orchestrated an RAF bombing raid to destroy the creature before it could germinate.

The Krynoid are also featured in the Eighth Doctor audio story for Big Finish entitled Hothouse, where an environmentalist group uses samples from the original Krynoid to try and create hybrids that can be controlled by the human host and thus control Earth's fauna to cope with the environmental damage, only for their efforts to merely create a rapidly-growing Krynoid before the Doctor sets it on fire.

A Krynoid appears as one of the villains in the Eleventh Doctor short story collection Tales of Trenzalore, as one of the creatures attacking Trenzalore during the Doctor's defence of the planet ("The Time of the Doctor", 2013), the Doctor defeating the Krynoid by blasting it with rapidly-freezing water from a specially modified hose and then shattering it with the reverberations of the town bell.

Macra
The Macra first appear in the Second Doctor story The Macra Terror (1967). They are an intelligent, giant crab-like species from an unnamed planet colonised by humanity in the future. The Macra invade the control center of the colony and seize the levers of power without the colonists – including their Pilot – knowing what had happened. Thereafter the Macra only appear at night, when the humans are in their quarters, observing a curfew. They have strong hypnotic powers which alter human perception. They also have the ability to ensure messages are vocalised through electronic apparatus such as television or sensor speakers. Both these tools are used to keep the human colonists under control, believing they are blissfully happy. This provides a cover for the Macra to use the colonists as miners in a vast gas mine. The gas is deadly to the miners but vital to the Macra, enabling them to move more quickly and rejuvenating their abilities. The Second Doctor effects a revolution on the Macra planet and helps engineer an explosion in the control centre, destroying the Macra in charge.

The Macra are also featured in the 2007 episode "Gridlock", becoming the first one-off opponent of the Doctor in the classic series to appear in the revived series, with the Zygons reappearing in the Eleventh Doctor story, "The Day of the Doctor" (2013). In the episode, some Macra are found to be alive below New New York, a city of New Earth. They live in the thick fog of exhaust gases on the main motorway under the city, tracking the flying cars by their lights and snatching at them when they get too close. The Doctor says that the species is billions of years old and once developed a small empire as "the scourge of this galaxy", but the Macra beneath New New York must have devolved into nothing more than beasts.

Mandrels
The Mandrels are furry, scaly bipeds native to the planet Eden, encountered in Nightmare of Eden (1979).

Marshmen
The Marshmen are amphibious humanoids from the planet Alzarius, encountered in Full Circle (1980).

Menoptra


The Menoptra appeared in the First Doctor story The Web Planet (1965). They are an intelligent, bipedal insectoid species from the planet Vortis. In appearance, they resemble a cross between giant butterflies and bees, with each Menoptra possessing four large wings. They have yellow and black stripes around their bodies and appear to be around six feet tall, but do not seem to have typical insect body parts (such as mandibles or an abdomen).

Peaceful and kindly by nature, the Menoptra move in a unique, stylised way and their vocal inflections are stilted. They were very welcoming of the First Doctor, Ian, Barbara, and Vicki; but showed an animosity towards their fellow insectoids, the Zarbi, as well as an abhorrence for the Animus, a hostile alien intelligence that had taken over the originally passive Zarbi and almost all of Vortis. Once it was clear that the Doctor was willing to help them defeat the Animus, they were only too glad to assist in any way they could.

Mentors
Mentors are amphibious capitalists who first appear in the serial Vengeance on Varos (1985).

Metebelis Spiders
Giant psychic spiders inhabited the planet of Metebelis 3, as seen in Planet of the Spiders (1974). The Metebelis Spiders were mutated Earth spiders. They are led by The Great One, a massive spider who has a web composed of Metebelis Crystals. The Third Doctor stole the last one needed during a prior visit to the planet, causing The Great One to go after him in order to complete her web. The Great One eventually completes her web, but the power of the web is too great, and it kills The Great One and all of her spiders, and causes mortal injury to the Third Doctor, causing him to regenerate. Kismet Delgado voices one of the spiders, while Maureen Morris voices The Great One.

Midnight Entity
The Midnight Entity is the conjectural name given to a mysterious being encountered by the Doctor in the episode "Midnight" (2008). The natural appearance of this organism is not directly known, only being referred to as a shadow, "something shifting. Like it was running". The creature was capable of possessing humans. First unable to move, it repeats what other people say, then begins saying what they are saying at the same time, then is capable of moving, taking over other people.

Minotaur
An alien Minotaur was kept in a prison that resembled an Earth hotel in "The God Complex" (2011). The "hotel" had never-ending corridors, and the Minotaur established itself as a God, feeding from the fears of the beings that find them trapped in the hotel. The Eleventh Doctor realised that actually, the Minotaur is feeding on the people's faith that something or someone will save them from their worst fears, and so temporarily encourages his companion Amy Pond to lose her faith in him, which eventually allows the Minotaur to die peacefully in the corridors of the hotel. The Doctor mentions that this alien species of Minotaur are cousins of the Nimon.

Monk
The Monks are an alien race of shapeshifting humanoids that can choose their appearance at will, first appearing in "Extremis" (2017). On Earth, they chose to resemble human corpses. The Monks study other planets through virtual simulations and take over by having someone in power consent to their rule out of love.

In "Extremis", the simulated version of the Twelfth Doctor eventually realized the truth and emailed a recording of the Monks' simulation to the real Twelfth Doctor through his sonic sunglasses, warning him of the coming invasion.

In "The Pyramid at the End of the World" (2017), the Monks showed the assembled world leaders a future where the Earth would be destroyed in one year by bacteria and offered to protect them as their rulers. The Doctor planned to stop the bacteria by blowing up the laboratory where it was found, but realized he could not escape the explosion due to his blindness. Unwilling to let her friend die, Bill Potts consented to the Monks' rule in return for the Doctor's eyesight, allowing him to escape.

In "The Lie of the Land" (2017), the Monks ruled over Earth for six months and kept the humans control by broadcasting a revised version of the planet's history that included the Monks from the beginning. Bill, the lynchpin through whom the fake history was broadcast, broke her psychic link with the Monks by broadcasting pure memories of her mother, causing the Monks to lose control over humanity and ultimately retreat from Earth.

Monoid
Monoids are shaggy-haired, one-eyed bipeds who work as servants on a space ark. They were encountered in The Ark (1966).

Movellan
The Movellans, who made their first appearance in the Fourth Doctor serial Destiny of the Daleks (1979), are an android species originating from outside the galaxy. They were adversaries of the Daleks.

Movellans outwardly resemble physically attractive humans of various ethnicities and genders. All Movellan androids wear white, form-fitting uniforms and have silver hair braided in a dreadlock style. They are stronger and have more physical endurance than human beings. A major weakness of the Movellan design is an external power pack which each android carries on its belt. This can be removed with comparative ease, causing the android to completely shut down. Once removed the power pack circuitry can be reprogrammed so that the android will obey the orders of another being.

The Movellans are mentioned again in Resurrection of the Daleks (1984), where a virus of their invention was central to that story's plot. They also appear in "The Pilot" (2017), where they are seen fighting the Daleks.

Nestene
The Nestenes are a race of amorphous aliens who can control all forms of plastic, first seen in Spearhead from Space (1970). The Nestenes can create humanoid plastic creatures called Autons. Since the Last Great Time War destroyed their food supply planets, the Nestenes have been seeking replacements.

Nimon
Black Minotaur-like beings with red eyes that go to other planets, posing as Gods, first seen in The Horns of Nimon (1979-80). However, they are nothing more than a parasitic race that bleed planets dry before moving on to new ones in a repeating cycle. They are cousins to the Minotaur species that the Eleventh Doctor encountered in "The God Complex" (2011). While one posed as a God, it acquired sacrifices to be used as batteries for powering their teleporter. However, the Doctor's arrival prevented more than two extra Nimons from arriving; the rest tried a last-resort plan by blowing up their now resource-deprived planet, killing them all.

Not-things
The Not-things, sometimes referred to as nobodies, are beings that existed within the emptiness outside the universe, encountered in "Wild Blue Yonder" (2023). Upon reaching the edge of the universe, they heard the sounds of hatred and war and were shaped by it, becoming malicious. They are able to copy other beings with incredible accuracy from their physical appearance to their memories as well while keeping a degree of flexibility allowing them to run faster or twist their bodies in unnatural ways. The Not-things mold copies by tapping into their subject's brain and converting heat in the air into mass to match their outer appearance. They can copy faster when the subject's brain is most active so they constantly scare their subjects, letting adrenaline and fear keep the brain active.

Ogri
The Ogri appeared in the Fourth Doctor story The Stones of Blood (1978).

The Ogri were a species of silicon-based creatures native to Ogros. They looked like large rocks, usually taller than a human but irregular in shape. They were large, slow and heavy, sometimes weighing as much as 3.5 tons, but they could take a lot of damage, both energy-based and physical. When they were awake, they would glow and make a loud rumbling noise. Like other silicon-based lifeforms, they broke down into grit when killed and also left silicon behind when they moved. They fed on various types of proteins which were common on Ogros. When on Earth, the Ogri had to rely on the globulin in blood, which they could absorb by touch. Ogri were not shown to communicate and did not show any signs of intelligence. Ogri had long lifespans, living for thousands of years. Cessair of Diplos took three Ogri from Ogros, which she used for protection and to impress the humans of Earth. These Ogri waited with the Nine Travellers until they were awoken by Cessair or her followers.

Ogron
Ogrons are mercenaries employed by various parties to "do their dirty work" throughout the universe, first appearing in Day of the Daleks (1972). They strongly resemble Orcs or Uruk-hai from The Lord of the Rings, being large humanoids with thick gray skin, protruding brow ridges, and thick, tangled hair. They primarily employ stun weapons, and have been employed by both the Daleks and the Master on at least one occasion.

Ood
The Ood are an intelligent species first encountered in "The Impossible Planet" (2006).

Optera
The Optera appeared in the First Doctor story The Web Planet (1965). These caterpillar-like creatures were once Menoptra, but they elected to instead burrow under the ground and abandon the world of light and flight above. It is implied that they may have been driven there by the malevolent Animus.

Plasmavore
Plasmavores are shape-changing aliens that live on haemoglobin, encountered in "Smith and Jones" (2007). They absorb blood from their victims, which in turn changes their own blood chemistry to that of the victim, allowing them to mimic other species when medically scanned. A Plasmavore was hiding from the Judoon in the Royal Hope Hospital on Earth, disguised as Florence Finnegan.

Primords
Mutagenic slime from under the Earth turned humans into savage Primords in Inferno (1970).

P'ting
The P'ting are small, apparently indestructible creatures encountered in "The Tsuranga Conundrum" (2018). The P'ting are not actively malicious, but have toxic skin and eat large amounts of inorganic material, making them hazardous due to being capable of eating spaceships. In the episode, the P'ting is let loose aboard the Tsuranga. The space station that the Tsuranga will dock at will destroy the ship if it detects the P'ting on board, but the Thirteenth Doctor is able to deduce that the P'ting is seeking out energy sources, and feeds it a fail-safe bomb from the ship's power source before jettisoning it into space. A P'ting later appears in "Revolution of the Daleks" (2021) where one is imprisoned in the same prison as the Thirteenth Doctor. The P'ting also appeared in online game Roblox as part of a collaboration between the game and Doctor Who.

The P'ting was created by writer Tim Price, who worked in the story room during series 11's development. The development team loved the "brilliant and unusual name for the alien."

Pyrovile
Pyroviles are alien creatures encountered in "The Fires of Pompeii" (2008).

Hailing from the planet Pyrovillia, these creatures had bodies made of rock that seemed to contain fire. Much taller than humans their heads resembled centurion helmets and they could be killed by contact with water. When their home planet vanished they fled and crash landed on earth reducing many of them to dust. They remained dormant beneath Vesuvius for centuries until an earthquake in Pompeii awoke them. They began to plan the conquest of earth using the city's soothsayers to their advantage. By having them inhale the dust of those destroyed in the crash the people of Pompeii began to turn to stone and would eventually become new Pyroviles. The Tenth Doctor learns of their plans to conquer Earth and boil the oceans and finds their lair in the heart of the volcano. But he learns that due to them using the volcano's power they are preventing the infamous eruption. Realizing that it was "Pompeii or the world" the Doctor and Donna reverse the machine triggering Vesuvius' eruption which destroys the Pyrovile.

Queen Bat
Queen Bats are used in The Caves of Androzani (1984) to produce an anti-toxin for spectrox.

Racnoss
The Racnoss appeared in 2006 Christmas special, "The Runaway Bride".

The Racnoss are described by the Tenth Doctor as an ancient race of aliens from the Dark Times of the universe. Half-humanoid, half-arachnid in appearance, they were an invasion force who consumed everything on the planets they conquered. Their race was wiped out by the Fledgling Empires, over 4.6 billion years ago. Although the Time Lords are not specified as being a part of the Empires, the Doctor acknowledges that his people unravelled their power source, Huon particles, and upon hearing the name of the Doctor's planet, Gallifrey, the Empress claims that they "murdered" the Racnoss. The Doctor and Donna Noble are shown witnessing nearly all of the survivors of the race escape in their ship to where the Earth would later form, serving in place of a planetesimal as its core, hibernating for billions of years, with the exception of their Empress. The Doctor notes that because the Huon particles ceased to exist, the surviving Racnoss are stuck in hibernation. The Empress is seen coming to Earth in her ship, the Webstar in this episode, seeking to use the Huon particles which had been recreated by the Torchwood Institute using the water of the River Thames as a means of reviving her "children" before feasting on the human population of Earth. The last Racnoss are presumed wiped out when the Doctor drains the waters of the Thames down the shaft leading to their ship; the Empress is killed when her own ship is destroyed by the British Army at the order of "Mr Saxon".

The Empress appears briefly in a flashback in "Turn Left" (2008). In the parallel universe created by Donna, she has still been defeated, but the Doctor, without Donna to stop him and ultimately save his life, is shown having drowned; a UNIT soldier speculates that he died "too fast for him to regenerate"; without his protection, the Earth is shown becoming a dystopia over the next few years.

The Racnoss also appear in the Doctor Who: Classic Doctors, New Monsters audio Empire of the Racnoss, which sees the Fifth Doctor being drawn into the war against the Racnoss in the distant past when a call for help during the war is picked up by a long-dormant program in the TARDIS, resulting in the Doctor being caught up in a political struggle between the Empress of the Racnoss and her traitorous old consort and her replacement consort.

Raxacoricofallapatorian
The Raxacoricofallapatorians first appeared in the Ninth Doctor episode "Aliens of London" (2005). They are native to the fictional planet of Raxacoricofallapatorius and may be grouped by extended family names which are sometimes used to refer to their species generically. They hatch from eggs and are composed of living calcium. Capital punishment is practised on the homeworld, which involves immersion of convicted criminals in acid that slowly dissolves them while still alive, which spectators then drink as a soup.

The Slitheen family were a ruthless criminal sect motivated by profit. After being convicted for their crimes on Raxacoricofallapatorius, they were exiled and threatened with execution if they returned.

The Blathereen family were sworn enemies of the Slitheen and infiltrated the prison on the planet Justicia. A pair of Blathereen appeared in The Gift (The Sarah Jane Adventures). This pair were created by the marriage of a member of both Slitheen and Blathereen families, and attempted to trick Sarah Jane Smith into accepting a gift of the Raxacoricofallapatorian plant Rakweed, which began to poison the Earth with deadly spores. The Slitheen-Blathereen had no interest in the Blathereen's law-abiding ways, and instead turned to the Slitheen's greed and need to make profit. After indulging on Rakweed, which was highly sensitive to sound, Mr Smith sounded an alarm which ultimately led to the Slitheen-Blathereen exploding.

Reaper
Reapers appeared in the Ninth Doctor episode "Father's Day" (2005). Although not named on screen, they were referred to as "Reapers" in the publicity material for the episode. The Reapers are parasitic creatures that feed on damage to the timeline, such as paradoxes. When Rose Tyler went to save her father, Pete Tyler from being killed prior to his wedding, it caused a paradox that released the Reapers. The Reapers disable the Doctor's TARDIS and begin to kill and feast on the people nearby, including the Ninth Doctor. The damage is undone when Pete kills himself by letting himself be run over by the car, allowing the timeline to go back to its proper state and banishing the Reapers.

Despite attempts by the production team to keep the episode low-budget, writer Paul Cornell sought to include Reapers in the episode, encouraged by BBC Head of Drama Jane Tranter in order to include more monsters into the series. The Reapers were initially designed as "men in cowls," based off the Grim Reaper. Though the design was changed, the scythe of the Grim Reaper persisted in their tails, which bore a resemblance to scythes. Due to the creation of the CGI being created later than scheduled, the production team had only two to three weeks to finish all of the VFX shots using the Reapers. The episode ended up being higher-budget than expected due to the inclusion of the Reapers.

In the comic story Four Doctors, a fight breaks out between the Tenth Doctor, Eleventh Doctor, and Twelfth Doctor, with the former two questioning the identity of the Twelfth. The three end up touching, creating a paradox that summoned the Reapers. The three Doctors are able to use their connection to each other to re-activate their TARDIS, which had been shut down by the Reapers, and de-materialize the TARDIS, forcing the Reapers to either leave the ship or be killed, dispelling their threat.

Rill
The Doctor encounters a Rill in Galaxy 4 (1965). While their appearance was ugly to human eyes, the Rill was quite friendly.

Rutan
An alien species who have been at war with the Sontarans for millennia, the Rutans first appeared on screen in Horror of Fang Rock (1977), although they were mentioned in the Sontaran story The Time Warrior in 1974. They appear as jellyfish-like glowing green spheres. Like the Zygons, Rutans can shapeshift at will. They are also vulnerable to certain sound frequencies. A Rutan appeared in "Horror of Fang Rock", where it attempted to invade the planet as a strategic outpost in their war with the Sontarans. The Rutans have since appeared in a variety of spin-off media, including books, audio dramas, and video games.

Sand Beast
The Sand Beasts are indigenous to the planet Dido, encountered in The Rescue (1965).

Saturnyn
Saturnyn are vampiric, lobster-like aliens that battled the Eleventh Doctor in 16th-century Venice in "The Vampires of Venice" (2010). Their appearance is fear-inducing due to many sharp protrusions and fangs. They were able to breathe underwater and had vampire-like qualities such as a vulnerability to sunlight, no reflections and a thirst for human blood. However, these are easily explainable; as "fish from space", they are used to living in the dark depths; anyone's mind cannot deal with conflicting information of a perception filter and a Saturnyn's true reflection; Rosanna and Francesco drank the blood of the girls attending the school so they could replace it with their own. Their leader, Signora Rosanna Calvierri used a perception filter to appear as a human woman, who started a school for girls; it was a guise for seeking victims to be transformed into mates for Francesco's brothers. They planned to flood Venice in an attempt to continue their civilization since their own planet Saturnyne was destroyed by cracks in the universe. When the Doctor foiled their plan, Rosanna committed suicide by allowing her brood to devour her. However, when the Doctor rewrote time in "The Big Bang" (2010) by preventing the cracks' existence, it is highly likely Saturnyne was not destroyed by the cracks and the Calvierri family did not end.

The Doctor, at least in his eleventh incarnation, considered his adventure battling the Saturnyns to be memorable. In "A Good Man Goes to War" (2011), he said his adventures were "running about, sexy, fish vampires, and blowing up stuff", and even asked Melody Pond if Amy told her about the "Vampires in Venice" during "Let's Kill Hitler" (2011).

Sea Devil
Sea Devils are turtle-like humanoids who first appeared in The Sea Devils (1972). They lived in Earth's oceans millions of years before humans evolved. They believed that a small planet would crash into Earth, which instead became Earth's moon. Like the Silurians, they went into hibernation and wanted to take the planet back from humans when they awoke.

Sensorite
Sensorites are an alien species encountered in The Sensorites (1964).

Shakri
The Shakri are a species spoken of in Gallifreyan myths, encountered in "The Power of Three" (2012). They are said to be the "pest controllers of the universe". They attack any species that they believe will pose a threat to the universe, hence why they tried eliminating humanity in the 21st century, years before they could colonise space in the future. A hologram of a wrinkled humanoid in a black robe was seen on the Shakri ship; however, it is not known if this is actually what the Shakri look like. The Shakri consider seven an important number, given they used that amount of portals, ships, cube activation time, and for a countdown. They follow something known as "the Tally"; the Doctor has implied that the Shakri compare a species' failures and successes to decide whether or not they will be subjected to "pest control".

The Silence
The Silence first appeared in "The Impossible Astronaut" (2011). Self-proclaimed "Sentinels of History", the Silence are genetically engineered members of the Papal Mainframe under the Academy of the Question. As they were originally created as confessional priests, Silents cannot be remembered unless they are being looked at, or if someone is wearing an eyedrive. In "The Time of the Doctor" (2013), with The Doctor's enemies converging on Trenzalore, the Papal Mainframe underwent a faith conversion into the Church of the Silence whose main belief is that "Silence will fall" to keep the Doctor from answering the oldest question in the universe "Doctor Who?" to avert a war caused by the Time Lords' return. However, a group of Silents under a splinter chapel led by Madam Kovarian wanted to completely avoid the Siege of Trenzalore by eliminating the Doctor: their attempts range from destroying reality in Series 5, which caused the events at Trenzalore, and using Melody Pond in an attempt to murder the Doctor in Series 6. The Silents still loyal to the Papal Mainframe remain and joined forces with the Doctor to fight back all the villains converging on Trenzalore.

Silurian
Silurians are a reptilian humanoid species first seen in The Silurians (1970).

Siren
The Siren appeared in "The Curse of the Black Spot" (2011). The Siren is a virtual doctor that was aboard a spaceship of an unknown alien race that crashed in a dimension parallel to the ocean the ship Fancy was sailing on in 1699. Thanks to "protein circuitry", she could appear before a species in a form that would be alluring to them for cooperation. To sedate her patients, the Siren could sing a beautiful vocal song. However, being nothing more than a program, the Siren had very little reasoning skills. The Siren turned red with demonic-looking face when faced with resistance and germs. When the ship she was doctor to crashed in a spatial rift where the Fancy had been becalmed (and the crew dead from a human disease), she impulsively started to take the injured of the ship, even if it was for a simple cut, showing a great lack of intelligence. Were it not for the Doctor's arrival, the Siren would eventually have reached shore and started trying to process anyone who was ill. Captain Henry Avery, Toby Avery and the crew of the Fancy took over the ship to give her someone to look after, and to see the universe.

Sisterhood of Karn
The Sisterhood of Karn first appeared in The Brain of Morbius (1976). They are a female religion situated on the planet Karn in charge of the Elixir of Eternal Life, made from the Eternal Flame. The Elixir has remarkable healing properties, such as aiding Time Lords undergoing difficult regenerations; the Fourth Doctor was given some after brain damage in a mental duel with Morbius. Other potions that the Sisterhood brew can allow Time Lords to choose what their next incarnation will be like; they range from age, weight, strength, emotion, sex and mindset. Seeing the person he had been for all his regenerations wasn't suited to combat the terror of the Time War, the Eighth Doctor choose a potion that would turn him into a Warrior.

They first appeared in the episode The Brain of Morbius, where they had grown paranoid as a result of a past betrayal by Morbius. Since then, they had been using their mental powers to crash ships onto the planet's surface. The Eternal Flame became clogged by soot one year prior to the events of the episode, and the Sisterhood had been trying to fix it to no avail. The Doctor solves the problem, and the Sisterhood later aid him in stopping the revived Morbius. They later reappear in the 2013 mini-episode "The Night of the Doctor," where they revive a mortally wounded Eighth Doctor, and help him regenerate into his next incarnation. They make further appearances in "The Magician's Apprentice" and "Hell Bent." The Sisterhood further appears in several pieces of Doctor spin-off media, including the audio dramas Zagreus, Sisters of the Flame, and Vengeance of Morbius.

Skithra
Skithras are an alien species encountered in "Nikola Tesla's Night of Terror" (2020).

Sky Fish
The Sky Fish are fish-like creatures seen in "A Christmas Carol" (2010). They are capable of swimming through the air using the electricity of the planet Ember's crystalline fog. They are attracted to music as it causes the crystals in the fog to resonate in a way that produces delta waves. They vary from small fish to fully grown sharks.

Slyther
The Slyther is a monster that serves the Daleks, seen in The Dalek Invasion of Earth (1964), guarding the Dalek mines in Bedfordshire. After the Slyther attacked a small group of humans, killing Ashton, Ian hit it with a rock, causing it to fall down a pit to its death.

Solonian
The Solonians are a race of humanoid creatures from the planet Solos, seen in The Mutants (1972). Their planet was colonized by the Overlords. The atmosphere contains a nitrogen isotope which causes the air to become toxic to humans in sunlight, although it has no effect on Solonians. Because Solos' environment changes drastically every 500 years, they must undergo major mutations periodically in order to survive.

Sontaran
A Sontaran first appeared as the antagonist in the Third Doctor serial The Time Warrior (1973–74). Commander Kaagh appears in Series 2 in the story "The Last Sontaran" after the destruction of his battle fleet as well as the death of the other Sontarans on board in the Doctor Who two-parter episodes "The Sontaran Strategem" and "The Poison Sky" (2008). He returns in "Enemy of the Bane", where he sides up with Mrs Wormwood, the recurring Bane. In the end, he sacrifices himself to foil her plans of the destruction of Earth. He makes a small appearance in "The Pandorica Opens" (2010). The Sontarans remain slightly miffed that they weren't allowed to fight in the Time War.

As seen with Strax, Sontarans can't tell the difference between men and women ("Two genders is a bit further than [they] can count"), and think polite terms such as Miss or Mister are military ranks.

Spiridon
The Spiridons featured in the serial Planet of the Daleks (1973). They are the dominant species of sentient humanoids on planet Spiridon in the Ninth System. They have developed a form of invisibility, capable of generating "anti-reflecting light waves". They become visible after death, having pale skin and a gaunt appearance. They wear heavy purple fur cloaks at night to protect themselves from the harsh nights of Spiridon. The Doctor returns to Spiridon in spin-off audio adventures Return of the Daleks and Brotherhood of the Daleks.

Star Whale
The Star Whale is a giant whale-like creature that appears in "The Beast Below" (2010). It's presumed to be the last of its kind, and is used to pilot the Starship UK, so as to save its citizens from the dangerous solar flares. The whale has the features of other animals such as an anglerfish's angler, an octopus's tentacles and a scorpion's tail, as well as having a bright pink hide with bioluminescent patches. It arrived on Earth as it heard the children of the United Kingdom crying, and was unable to bear the sound. Believing its arrival to be a one-in-a-million miracle, the people of Britain captured it and built their ship around it, torturing it via powerful electric pulses, administered directly into the opened pain center of the Whale's brain, in order to keep the ship flying. Over the years, they realised that they could not justify keeping the creature in agony, but feared that if they set it free, the ship and all those aboard would be destroyed as the creature fled, so they chose to instead forget, and fed those who protested to the beast. When the Doctor learnt of this, he decided to render the creature brain-dead, ending its suffering and saving the lives of all those on the ship, but Amy set it free, revealing that the whale had volunteered to help, and that contrary to the beliefs of the station's masters, that it would continue flying without the need to torture it. The creature's exact size is not specified, and it is only visible in its entirety towards the episode's ending.

Stenza
The Stenza are a warrior race who possess sub-zero body temperatures, first seen in "The Woman Who Fell to Earth" (2018). As physical contact with any part of them can cause death from sub-zero burns, Stenza require the use of specialised suits to be able to interact safely with other lifeforms. The Stenza maintain two traditions amongst their people – a ritualistic hunt to earn the right of leadership, in which a Stenza hunts a randomly selected quarry without the use of weapons or any form of aid; and collecting a tooth from a kill to later apply to their face. The Stenza are noted for conducting ethnic cleansing on planets they conquer, as revealed in "The Ghost Monument", using the conquered populace to create weapons for their use.

The Swarm
The Swarm was seen in "Planet of the Dead" (2009). Also known by the Unified Intelligence-Taskforce (UNIT) as Stingrays, they are flying manta ray-like creatures, with metal exoskeletons that allow them to travel from planet to planet via wormholes. They consume everything on a planet, turning it into desert; and then swarm over the planet's surface, generating a wormhole which allows them to travel to the next planet.

The Stingrays are apparently arthropods, as they are exothermic, and possess an exoskeleton composed of metal that has been ingested then exuded to the exoskeleton. They are voracious feeders, eating both organic and inorganic materials ranging from flesh and bone to plant matter to metals and plastic. They also produce vast numbers of young and grow from birth to adult in under a year, as shown when the Tenth Doctor shows a year-old clip of San Helios before its Stingray infestation.

They travel to other planets through wormholes created in the fabric of Spacetime by circling a planet faster and faster, and as each swarm can contain billions of giant stingrays, they rip a hole in space. Their wormholes can transport the whole swarm an infinite distance through space.

Sycorax


The Sycorax first appeared in the debut Tenth Doctor story "The Christmas Invasion" (2005).

The Sycorax appear to be skinless humanoids wearing mantles of bone, usually keeping their features concealed under helmets. They are proficient in the use of weapons like swords and whips, the latter which can deliver an energy discharge that disintegrates the flesh of its target. Their language is called Sycoraxic. The Sycorax also appear to have technology that is either disguised or treated as magic, referring to "curses" and the Doctor's regenerative abilities as "witchcraft". The Sycorax leader referred to an "armada" that they could use to take Earth by force if their blood control plan failed. They also appear to have a martial society, with traditions of honourable combat, yet they have no qualms about killing prisoners.

In The Doctor Who Files books, the name of the Sycorax homeworld is given as "Sycorax". It is unclear if this is another name for the Fire Trap. Furthermore, after the destruction of the Fire Trap, the Sycorax spread further through the galaxy, and like humans are one of three species that continually survive and adapt, even unto the End of the Universe.

The name Sycorax is used in William Shakespeare's play The Tempest. Shakespeare's Sycorax has died before the play begins; she is described as a witch who was the mother of the beast Caliban. The Shakespearean name is referenced in the third series episode "The Shakespeare Code" when the Doctor finds a horse's skull in The Globe's prop cupboard. He comments that it "Reminds [him] too much of the Sycorax". Shakespeare remarks he likes the sound of the word, obviously then going on to use it in The Tempest.

The Sycorax also make a brief appearance in "The Pandorica Opens" (2010) as part of The Alliance formed to trap the Doctor. Later, in "The Name of the Doctor" (2013), the Great Intelligence mentions them as one of those that left the Doctor blood-soaked. A Sycorax appears as a prisoner alongside the Doctor in "Revolution of the Daleks" (2021).

In issue #1 of the IDW published Doctor Who comic book, a Sycorax is collecting near-extinct species to use with shape-shifters for expensive hunts. The Sycorax race also make a return in the Tenth Doctor comic strip "The Widow's Curse", in Doctor Who Magazine #395. The DWM comic story is the first appearance of female Sycorax, who seem to operate separately from the males.

In the audio series Classic Doctors, New Monsters, the Seventh Doctor faces the Sycorax in the audio "Harvest of the Sycorax", where he has to stop their efforts to take control of a space station that contains blood samples taken from virtually the entire human race of the far future.

Taran Beast
Taran Beasts are the furry species seen in The Androids of Tara (1978).

Tenza
The Tenza are an alien species that has their young raised by other species, seen in the episode "Night Terrors" (2011). Put simply, "a Tenza's sole function is to fit in." They adapt perfectly to what their foster parents want, such as "George" becoming the son Claire was unable to give birth to. Tenzas have powerful psychic abilities such being able to create monsters with just their imagination, as well as mentally creating massive perception filters that alter their foster parents' memories.

Terileptil
The Terileptils appeared in the Fifth Doctor serial The Visitation (1982). They are a reptilian humanoid species. They cannot survive long without breathing soliton gas, which is highly combustible when combined with oxygen. As an advanced society, they enjoy a heightened appreciation of both aesthetics and warfare and have been known to employ bejewelled androids. Criminal punishment in Terileptil society includes life imprisonment working in tinclavic mines on the planet Raaga, often with substandard medical care.

In 1666, a group of Terileptil prison escapees hidden near London attempted to use a genetically enhanced version of the Black Plague to destroy humanity. The destruction of their lab in Pudding Lane caused the Great Fire of London.

Tetrap


The Tetraps are a bat-like race from the planet Tetrapyriarbus, seen in the Seventh Doctor's debut story, Time and the Rani (1987). A pack of Tetraps was employed by the Rani to help defend her Giant Brain. The Rani armed a pack of Tetraps for this purpose and used them as general henchmen to terrorise the native Lakertyans.

Tetraps have four eyes, one on each side of their head, giving them all-round vision, and put this to good use in stalking fugitives. Like bats, they sleep by hanging upside-down in a cavern. They feed off a dark red-coloured sludge that the Lakertyan leader releases down a chute into a trough.

Tetraps possess limited intelligence, but they soon realise that the Rani's plans would have them all killed on Lakertya. This is confirmed when their leader, Urak, hears of her plans and she later leaves him to guard over her laboratory rather than take him with her in her TARDIS, thus condemning him to death. Urak and the enraged Tetraps capture the Rani in her ship and take her back to their home planet, to force her to help solve their natural resource shortages.

Thal
The Thals are a race of peaceful, blond humanoids first seen in The Daleks (1963-64) who, together with the Daleks, are natives of the planet Skaro. Once a warlike species, a nuclear conflict with the Daleks, which nearly wiped out all life on their home planet, led them to develop a pacifist, agrarian society.

Tharil
The Tharil are a humanoid race of lion-like creatures seen in Warriors' Gate (1981). Hailing from E-Space, their world is connected to a gateway between E-space and N-space. They are time-sensitive and are able to use their powers to traverse the universe. Thanks to this, they were able to enslave many people. However, their empire crumbled when the slaves rebelled, building robots that were able to overcome the Tharils. The tables were turned and the Tharils became the slaves, forcefully used by their captors to navigate through time and space. One Tharil brings the Fourth Doctor and his companions to the gate. When the Doctor learns of their history, he agrees they have suffered enough for their crimes, and helps free the Tharils on the slavers' ship. As the Doctor and Adric leave, Romana and K9 remain behind, to help the Tharils free slaves on other planets.

Time Beetle
The Time Beetle first appeared in "Turn Left" (2008). It is a member of the Trickster's Brigade, a group of aliens that serve the Trickster. The Time Beetle, similar to the Trickster himself, feeds on time energy and can cause a victim to change a decision they made in the past, thereby altering history. The change in history is usually very minor, affecting only the person the beetle attaches to, and the universe usually "compensates" for the discrepancy.

When the beetle attaches to Donna in "Turn Left", instead of compensating it creates a "great big parallel world" where Donna never meets the Doctor, resulting in disaster for Earth. The Doctor, Martha Jones, Sarah Jane Smith, and Torchwood staff Ianto Jones and Gwen Cooper are all killed, the city of London is completely destroyed when the Titanic crashes into Buckingham Palace, Captain Jack Harkness is taken to the Sontaran homeworld, and millions of people die from threats the Doctor would have otherwise prevented. Donna travels back in time to make her make the original decision that leads to her meeting the Doctor, killing the Beetle. According to both the Doctor and Donna, this universe ceased to exist.

Time Lord
The Time Lords are a race of humanoid aliens to which the Doctor, among other characters, belongs. Time Lords have the ability to regenerate when mortally wounded. This process creates for them an entirely new body and results in major changes in personality, but retains the Time Lord's memories and identity. It is suggested in The Power of the Daleks (1966) that some detectable feature is retained, as the Daleks are immediately able to recognize the Second Doctor, even though he has just regenerated. During "The Time of the Doctor" (2013), it was confirmed by the Eleventh Doctor that a Time-Lord, naturally, is only allowed 12 regenerations, resulting in 13 different incarnations. In the same episode, the Doctor saves Clara's life by sending her home to her own time, but in protest she clings to the TARDIS through the Time Vortex on its return. Upon arriving 300 years later, she finds a visibly aged Doctor, proving that Time Lords experience natural physical changes during each lifespan between regenerations. In the episode "A Good Man Goes to War" (2011), it is suggested this ability evolved due to the Time Lord race's long-term exposure to the untempered schism.

Time Lords exhibit various other superhuman abilities, including certain mental powers, and resistance to otherwise harmful effects such as extreme cold and radiation. They possess a binary vascular system (two hearts), and therefore a faster heart rate, as well as a cooler internal body temperature. The Doctor would later claim that Time Lords came before humans did in "The Beast Below" (2010).

The first Time Lord to appear other than the Doctor and his granddaughter Susan Foreman is the Monk, in the 1965 serial The Time Meddler, however his race is not confirmed. The term itself is not used until The War Games (1969), when the race as a whole is introduced.

As of the 2005 revival series, the Time Lords are essentially extinct, apart from the Doctor, as they have been destroyed by him during the Time War. However, "The Day of the Doctor" (2013) shows that this was a ruse; the Time Lords are still alive in pocket universe, where all of the Doctors put them to save them from destruction.

Time Zombies
Creatures that appeared in "Journey to the Centre of the TARDIS" (2013). They are echoes of the possible future selves that the Doctor, Clara, and Trickey and Gregor Van Baalen would have become from being exposed to the Eye of Harmony too long; they were burnt by it as their cells liquified.

Unlike the other time echoes, they could touch the present world, and killed Bram Van Baalen. They end up trapping their past selves in the Eye of Harmony's room by accident, setting up the existence of the Time Zombies. The Doctor realises how to avert the future, killing all but Clara's echo by knocking them off the rail. However, the Van Baalens couldn't avoid their fate. The Doctor eventually prevents the existence of the zombies by resetting time, preventing the TARDIS from being damaged and salvaged by the Van Baalen Brothers.

Tivolian
The Tivolians appeared in "The God Complex" (2011). They are a cowardly rodent-faced race that live on Tivoli, the most invaded planet in the galaxy. As a result, they have designed their cities to be comfortable for invading armies and their national anthem is "Glory To ". They are known for surrendering as soon as possible, and actually enjoy being conquered. As a result of the natives' cowardly attitudes, the planet Tivoli has lasted longer than any of the greater civilizations. They do not assert their own opinions often, just wishing to be ordered around or enslaved, as seen in the case of Gibbis and Albar Prentis. The Twelfth Doctor says that Tivolians wouldn't say "Boo" to a goose—they'd be more likely to give the goose their car keys and bank account information. Among the list of those who ruled the Tivolians are the Fisher King and the "glorious Arcateenians".

Toclafane
The Toclafane are the last remnants of humanity from the year 100 trillion, first seen in "The Sound of Drums" (2007). Originally intending to travel to Utopia, the last refuge of a dying universe, they find nothing but "the dark and the cold" of space. Losing the last shred of hope they had, they turned on themselves, cannibalising their own bodies to create a new cyborg race. As part of this process they regress into little more than children with shared memories. The name Toclafane is given to them by The Master, who takes it from the Gallifreyan equivalent of the bogeyman.

The Toclafane's cyborg forms possess energy devices capable of killing and disintegrating targets. They are equipped with numerous retractable blades. The first four to be seen also exhibit apparent teleportation or cloaking abilities, not displayed by others of their race. All that remains of their bodies are barely recognisable human faces wired into basketball-sized mechanical spheres.

In "The Sound of Drums" and "Last of the Time Lords" (2007), the Master rescues four Toclafane from the end of the universe prior to an eventual Big Freeze, using them to fake a first contact situation in order to draw the world's leaders into one place for easy capture. He then uses a "paradox machine" to allow the future of the human race to slaughter many in the present, in short bringing the six billion humans that are alive in the year 100 trillion to return in the form of the Toclafane. The paradox machine creates a temporal paradox, allowing them to kill their ancestors without damaging themselves, and thus establish the Master's rule over Earth. After subduing Earth, the Master aims to establish a new Time Lord empire with himself as the leader and the Toclafane as his people and ground troops. This plan is foiled when the paradox machine is destroyed, causing time to rewind and trapping the Toclafane back at the end of the universe. Once the Master loses control of Earth, the false name Tocalafane is discarded for a more generic "spheres".

The Toclafane feature on the cover of the New Series Adventures novel, The Story of Martha, which chronicles Martha Jones's adventures during The Year That Never Was.

Torajii
A sentient star featured in the episode "42" (2007). The crew of a cargo ship uses a sun scoop on Torajii to refuel their ship, unaware that it is actually a living organism. Torajii then uses the stolen matter to possess and kill the crew until the fuel is returned. Once the sun scoop is dumped, it allows the ship to fly away.

Tractator
Tractators are giant insects with incredible power over gravity, seen in Frontios (1984).

Trakenite
Trakenites are a humanoid species with great intelligence, seen in The Keeper of Traken (1981). They live on the peaceful planet of Traken, which is part of the Traken Union. A Keeper is chosen to guard the Source once the life of the current one draws close to ending. Their planet would petrify anything evil that would arrive, until the Keeper's life began waning and thus the petrification would weaken. During "Logopolis" (1981), the Master caused the destruction of the Traken Union and its people by unleashing entropy back into the universe, leaving Nyssa (as far as she or anyone knew) the sole Trakenite in existence.

Trees
Humanoid Trees from the Forest of Cheem are seen in "The End of the World (Doctor Who)" (2005). The Ninth Doctor meets Jabe and her attendants, Lute and Coffa, when they attend the viewing of the destruction of Earth on Platform One. They are descended from the rain forests of Earth.

Trion
Trions are a humanoid species first seen in Mawdryn Undead (1983). A civil war broke out on the planet, and those on the wrong side were banished to different planets, Turlough ended up on Earth, while the rest of his family ended up on a volcanic planet. The descendants of the original exiles came to believe the mark of exile meant those who had it were chosen by their god, Mulkur, to lead them. After several years past, the exile was lifted from those banished from the planet, allowing them back home.

Tritovore
Tritovores are humanoid fly creatures that appeared in "Planet of the Dead" (2009). They trade with other civilisations for their excrement. They communicate with clicks that the TARDIS did not translate because it was not on the same planet as the Tenth Doctor and Lady Christina de Souza. The Doctor speaks with them through their own language while they understand The Doctor through a one-way telepathic translating communication device.

Tythonian
Tythonians are enormous creatures seen in The Creature from the Pit (1979).

Urbankan
Urbankans are green-skinned humanoids encountered in Four to Doomsday (1982).

Usurian
The Usurians from the planet Usurius are a species that abandoned military conquest in favour of economic conquest, encountered in The Sun Makers (1977). They enslaved humanity after their engineers made Mars suitable for human habitation, humans having depleted the Earth's resources. Once humanity had depleted Mars's resources as well, the Usurians engineered Pluto so that humans could inhabit it. They created six artificial "Suns" around it and installed the Collector to oversee the collection of taxes from their human workforce. They intended to abandon Pluto and leave humanity to become extinct once the humans had exhausted its resources, there being no economically viable planet to relocate humanity to once more. The humans on Pluto revolted against the Collector and seized control of Pluto. The revolutionaries intended to relocate to Earth as the Doctor assured them it would have regenerated in their absence.

The Usurians have knowledge of the Time Lords, graded as "Grade 3" in their "latest market survey", considering Gallifrey to be of low commercial value. Usurians can adopt a humanoid form but in their natural state they resemble seaweed. Shock can force them to revert to their natural form. According to the Doctor, Usurians are listed in a "flora and fauna" of the universe written by a Professor Thripthead under poisonous fungi.

Uvodni
The Uvodni is a bug-like race, first introduced in "Warriors of Kudlak" (2007). General Kudlak served in his race's military until injuries forced him to retire. In order to gain more troops for his race's continuing war effort, Kudlak was dispatched to Earth. He seized control of the Combat 3000 laser game franchise, which he secretly used to find human children with strong combat skills. These children were teleported to Kudlak's orbiting spaceship and dispatched to fight in his race's war. Kudlak took orders from a battle computer that used the image of a female of his race as an avatar, which he referred to as "Mistress". An error left the computer unable to comprehend the concept of the war ending, so it withheld from Kudlak an announcement of peace from his emperor for over a decade. When this fact was revealed, by intervention of Luke Smith's computer hacking, Kudlak destroyed the computer. He then dedicated his life to finding and returning the already dispatched human children, hoping to gain inner peace by doing so.

Uxariean
Uxarieans are creatures from the planet Uxarieus, seen in Colony in Space (1971).

Vardan
The Vardans are first encountered in The Invasion of Time (1978).

Varga Plant
The Varga Plants appeared in the First Doctor episode "Mission to the Unknown" and the serial The Daleks' Master Plan (1965–66). They were created by Terry Nation.

Varga Plants grew naturally on the Daleks' homeworld, Skaro, and when the Daleks set up a base on the planet Kembel they brought some Varga plants with them to act as sentries in the jungle surrounding their base. They were suited to this as they could move around freely by dragging themselves along with their roots.

Varga plants resemble cacti; they are covered in fur and thorns. Anyone pricked by a Varga thorn will be consumed by the urge to kill, while simultaneously becoming a Varga plant themself. This grisly fate befell astronauts Jeff Garvey and Gordon Lowery, and their commander, Marc Cory, was forced to kill them.

Vashta Nerada
Vashta Nerada (literally: the shadows that melt the flesh) are first encountered in "Silence in the Library" (2008). They are microscopic swarm creatures which, when present in a high enough concentration, are indistinguishable from shadows, and use this to their advantage in approaching and attacking prey. They are described as the "piranhas of the air", able to strip their victims to the bone in an instant in high enough densities. The Tenth Doctor says that almost every planet in the universe has some, including Earth, and claims that they can be seen as the specks of dust visible in bright light. He states they are the reason most sentient creatures have an instinctual fear of the dark. On most planets, however, Vashta Nerada exist in relatively low concentrations, feeding primarily on carrion, with attacks on people being comparatively rare. In the episode "Silence in the Library", an unusually high concentration of Vashta Nerada had completely overrun the 51st-century "Library", resulting in the apparent death of everyone inside at the time.

Vashta Nerada normally live in forested areas, and reproduce by means of microscopic spores which can lie dormant in wood pulp. In the episode "Forest of the Dead", this is revealed to be the reason for their unusual prevalence in The Library, as it is made known that the books and The Library itself was constructed of wood from the Vashta Nerada's native forest feeding grounds. Individually, Vashta Nerada are non-sentient, but if a large enough concentration come together, they can form a group mind of human-level intelligence capable of communication.

The fourth episode of Doctor Who: The Adventure Games, "Shadows of the Vashta Nerada", features them as the leading villain when a temporal rift draws a swam of Vashta Nerada to an underwater base that is being visited by the Eleventh Doctor and Amy Pond.

The Vashta Nerada appear in the second volume of the Big Finish Productions audio Classic Doctors, New Monsters; "Night of the Vashta Nerada" sees the Fourth Doctor visiting a theme park that has unleashed the local Vashta Nerada after the planet's forests were torn down to allow the park to be constructed, and "Day of the Vashta Nerada" pits the Eighth Doctor against genetically-altered Vashta Nerada that have been created as a new weapon in the Time War.

Vervoid
Vervoids are artificially created plant-based humanoids that appear in Terror of the Vervoids (1986). They were created as slaves to humanity, but began to rebel and attempt to kill all animal lifeforms. The Sixth Doctor is forced to commit genocide against the Vervoids, which is later used against him when he is put on trial by his species, the Time Lords. The Vervoids were noted for their design, which was described as appearing to be sexual in nature. The design caused conflict when Doctor Who season 23 was released on VHS, with one country refusing to release the season with Terror of the Vervoids included due to the design.

Vespiform
Vespiform are an insectoid species resembling giant wasps, encountered in "The Unicorn and the Wasp" (2008). They were born en masse in hives in the Silfrax Galaxy. Each possesses the ability to morph into other species. It also has the ability to breed with other species, including humans, to produce offspring.

Vespiform have a telepathic connection to objects called firestones, which contains part of their mind. Like Earth's wasps, the Vespiform are vulnerable to water. A Vespiform-human hybrid can live a normal life as a human until a burst of intense emotion awakens its alien biology. When the Vespiform morphs into another species it emits a purple light.

In "The Unicorn and the Wasp", a Vespiform appears and goes on a killing spree in the style of Agatha Christie's murder mystery books. Eventually it turns out the reason for Vespiform's killings was due to his firestone in the possession of Lady Eddison, who was thinking about Christie's novels. Furthermore, the Vespiform is revealed to be Lady Eddison's illegitimate son: Reverend Golightly. In the end, trying to get the firestone back, the Vespiform dies chasing after the item when Donna Noble throws it into a lake.

Vogan
Vogans were encountered in Revenge of the Cybermen (1975). Vogans are the native population of the planet Voga, which was made entirely of gold. The Cybermen sought to destroy Voga, as humans were using Voga's gold to gain an advantage in the Cyber Wars, wars fought against humans and the Cybermen. The Vogans were aided by the Fourth Doctor, who helped them defeat the Cybermen. Two of the Vogans who appeared in the episode Vorus and Magrik, were portrayed by actors David Collings and Michael Wisher, respectively. It is believed that Wisher's performance in the episode led to him being cast as recurring antagonist Davros in the later serial Genesis of the Daleks.

Voord
The Voord are a race of amphibious humanoids introduced in the First Doctor serial The Keys of Marinus (1964). The Voord attempted to work with their leader, Yartek, to gain the Keys of Marinus in order to obtain the Conscience of Marinus, which they seek to use for their antagonistic purposes. The Voord are thwarted when Yartek takes a fake key, resulting in his death. The Voord were created by Terry Nation, who had also created the Daleks, with costume designer Daphne Dare creating the visual design for the creatures. The Voord were portrayed by actors Martin Cort, Peter Stenson and Gordon Wales, while Yartek was portrayed by Stephen Dartnell.

The Voord appeared in spin-off media. In the comic The World Shapers, the Voord are revealed to have evolved into Cybermen, with Marinus becoming the Cybermen's home planet of Mondas. The events of the comic strip were later referenced in "The Doctor Falls" (2017), where the Twelfth Doctor refers to Marinus as one of the planets the Cybermen originated from. They later appeared in the audio drama Domain of the Voord, in which the First Doctor and his companions fight against an invading group of Voord on a spaceship known as the Hydra. The Voord later re-appeared in the Titan Comics strip Four Doctors. It is revealed in the comic that the Voord fought in the Time War, causing the species to evolve into a more powerful, muscular state. An alternate Twelfth Doctor, following his betrayal by Clara Oswald in "Dark Water" (2014) allied with these hyper-evolved Voord, who hid themselves in a pocket universe to escape the vengeance of the Time Lords, who they feared would remove the hyper-evolved state of their species. The Tenth Doctor ends up being forced to regress the Voord back to their pre-Time War state in order to defeat the alternate Twelfth Doctor.

Weed Creature
A powerful weed took over an off-shore gas rig in Fury from the Deep (1968); it had the ability to take over human minds.

Weeping Angel
The Weeping Angels first appeared in "Blink" (2007).

Wirrn
The Wirrn are an insectoid race that made their debut in The Ark in Space (1975).

The Wirrn claim to have originated from Andromeda (whether they meant the galaxy, the constellation, or even a planet named "Andromeda" is unclear), but were driven into space by human settlers. They are slightly larger than humans, dark green and wasp-like in appearance, and live mostly in space, although their breeding colonies are terrestrial. Their bodies are a self-contained system, their lungs being able to recycle waste carbon dioxide and only needing to touch down occasionally on planetary bodies for food and oxygen. The Wirrn's life cycle involves laying their eggs in living hosts; the larvae emerge to consume the host, absorbing its memories and knowledge. A Wirrn larva is a green slug-like creature, varying in size from a few inches to 1 or 2 metres across. It can "infect" another organism through contact with a substance it excretes, mutating them into an adult Wirrn and connecting their consciousness to the hive mind.

In "The Ark in Space", the Wirrn found Space Station Nerva in orbit around an Earth devastated centuries before by solar flares. The survivors had lain in suspended animation waiting for the planet to recover, but had overslept by several millennia. The Wirrn intended to use the sleepers as a food source and claim the empty Earth for their own, as both a means of survival and an act of revenge against the human race for taking their former territories. In the course of their plan, Noah, leader of Nerva, was infected and converted to their kind. However, Noah still retained "more than a vestige of human spirit", probably thanks to the encouragements of the Doctor, and led the Wirrn into Nerva's transport ship even though he knew it was rigged to explode. It did so, ending the Wirrn threat.

The Wirrn have also appeared in the Eighth Doctor Adventures novel Placebo Effect by Gary Russell, and in the audio play Wirrn: Race Memory, produced by BBV. Big Finish used them in the audio stories Wirrn Dawn with the Eighth Doctor and Wirrn Isle with the Sixth. A dead Wirrn appears briefly in the television story The Stones of Blood.

Wrarth Warrior
The Wrarth Warriors are a police force who appear in "The Star Beast" and the original comic upon which the episode is based. They seek to hunt down and capture the villainous Meep. At the end of the episode, the Wrarth capture the Meep and take him into custody. Actor Robert Strange portrayed one of the lead Wrarth, known as Sergeant Zogroth. The Wrarth actors used wore stilts in order to depict the Wrarth's height, and worked with Doctor Who creature movement director Paul Kasey in order to determine the Wrarth's "physicality" in the episode.

Xeraphin
The Xeraphin were an ancient species encountered by the Fifth Doctor in the story Time-Flight (1982). Originating from the planet Xeriphas, they possessed immense psychokinetic and scientific powers. Their planet was destroyed in a war between two other species, with the surviving Xeraphin crash-landing on prehistoric Earth. Due to intense radiation, they merged into a gestalt. The Master arrived on prehistoric Earth shortly after the radiation began to subside. The Master attempted to use the Xeraphin to power his TARDIS, but is thwarted by the Fifth Doctor. The Xeraphin in the episode were portrayed by actors André Winterton and Hugh Hayes.

Zarbi
The Zarbi appeared in The Web Planet (1965), and are an ant-like insectoid species, with some characteristics associated with beetles, from the planet Vortis, which were controlled by the power of the Animus. The Zarbi possessed little intelligence and fell under the Animus's control, becoming the animus's foot-soldiers. They had sentient weapons known as Larvae Guns (or Venom Grubs) which they used to enforce their will. They returned to normal after the defeat of the Animus, and returned to a peaceful existence with the other inhabitants of Vortis.

The Zarbi were named by the wife of writer Bill Strutton. Set and effects designer John Wood used descriptions by Strutton to sketch designs for the Zarbi, with Wood wanting the Zarbi to be realistic whilst also hiding the human element. Four costumes were constructed, with producer Verity Lambert loving the design, though many other crew members were more hesitant about the feasibility of the Zarbi. The outfits were modelled on actor Robert Jewell, and took around thirty minutes to put on. Jewell, Kevin Manser, John Scott Martin, and Gerald Taylor portrayed the Zarbi on-screen. A special trailer for The Web Planet, featured the Zarbi at the BBC Television Centre before being shown to their dressing rooms, was aired prior to the episode's airing, with the trailer being made to take "the curse out of the Zarbi" for younger viewers of the episode. The Zarbi were planned to re-appear in a brief cameo in the 2024 episode "The Legend of Ruby Sunday," though this was scrapped.

The Zarbi later re-appeared in several spin-off stories. The comic story On the Web Planet, published in TV Comic, depicted the First Doctor and his grandchildren John and Gillian discovering that the Zarbi had once again turned against the Menoptera, another species that inhabited Vortis. They later discovered that the Zarbi were actually devices piloted by an alien species known as the Skirkons, who had enslaved the real Zarbi as well as the Menoptera. The First Doctor managed to free all the races and defeated the Skirkons. A short story published in the Doctor Who Annual 1966, titled The Lair of Zarbi Supremo, depicted a mutation, which causes a Zarbi to mutate into the Zarbi Supremo. The Supremo takes control of the rest of its kind and turns Vortis into a rogue planet, sending it to invade Earth. The First Doctor is able to kill the Supremo and free the Zarbi from their subjugation. A later comic, published by Titan Comics, titled Unnatural Selection, depicted the re-formation of the Animus, who is sent to the London Underground with the help of Adam Mitchell. The Animus used the Zarbi as its minions once more until the First Doctor's companion Ian Chesterton hit the Animus with a train, defeating it. The First Doctor then returned the freed Zarbi home.

Zocci
The Zocci are a diminutive race of red spiked aliens. "Voyage of the Damned" (2007) featured a Zocci named Bannakaffalatta, who aids the Tenth Doctor in attempting to stop a space-faring version of the Titanic from crashing into the Earth. In "The End of Time" (2009-10), a species related to the Zocci, except green and more human-like in size, known as the Vinvocci, appeared. A pair of them attempted to take a Vinvocci medical device away from a human, named Joshua Naismith, who attempted to re-program the device to make his daughter immortal. They later aided the Tenth Doctor in stopping the Master after he used the device to turn every human on Earth into a copy of himself. Actor Jimmy Vee portrayed Bannakaffalatta.

Zolfa-Thuran
A race of intelligent cacti from the planet Zolfa-Thura. Meglos, from the episode of the same name, is the last surviving member of the species. Meglos used the natural shapeshifting abilities of his species to obtain an item known as the Dodecahedron, which contained immense power. He planned to use the Dodecahedron to destroy the neighboring planet of Tigella, but is thwarted by the Fourth Doctor, who instead rerouted the Dodecahedron to destroy Meglos and Zolfa-Thura. Meglos was planned to re-appear in "The Lodger," (2010) but this was scrapped due to his similar appearance to the Vinvocci, who had appeared recently at that point in the series. A version of the Fourth Doctor, based off his appearance when Meglos shapeshifts into him, was featured in the Madame Tussauds waxwork museum in the early 1980s alongside a waxwork model of the Fourth Doctor.

Zygon
The Zygons are shape-shifting aliens first encountered in Terror of the Zygons (1975). In the episode, the Zygon home world had been destroyed, and they attempted to conquer the Earth in order to claim it as their new home world. They later re-appeared in the fiftieth anniversary special "The Day of the Doctor," (2013) where they attempted to conquer the planet once more. The Zygons and humans negotiate a treaty, leading to Zygons living among humans on Earth. In "The Zygon Invasion" and "The Zygon Inversion," (2015) a splinter group of Zygons is unhappy with having to hide away among humans, and attempt to change the status quo so they can live in their natural forms. The Twelfth Doctor is able to negotiate with the splinter group's leader, Bonnie, and come to a peaceful solution. The Zygons in Terror of the Zygons were portrayed by actors Keith Ashley and Ronald Gough, while the Zygons in "Day of the Doctor" were portrayed by actors Aidan Cook and Paul Kasey, with Nicholas Briggs providing their voice.

An unofficial erotic spin-off film produced by BBV Productions, known as Zygon: When Being You Just Isn't Enough was produced in 2005.

The Zygons were conceived by writer Robert Banks Stewart, and designed by James Acheson as part of a collaboration with John Friedlander. Then director Douglas Camfield also influenced the final appearance. They were designed to resemble "oversized embryos." The Zygons were initially planned to be able to "sting" their victims, akin to jellyfish, but this concept was not elaborated on in the episode and hard to notice in the final story.

The Zygons in Terror of the Zygons additionally brought with them a creature known as the Skarasen, which had resided in Loch Ness for so long that it had become known as the Loch Ness Monster. The Zygons fed on the milk it produced, which is why they brought it with them. The Skarasen was filmed using a puppet hung by wires, with other scenes depicting the Skarasen being filmed in stop motion.