Talk:Half-Life (series)/merge

Race X is a hostile alien race featured in the computer game series Half-Life by Valve Software. They appear only in the Opposing Force expansion pack, and very little is revealed about them. Race X aliens appear late in the timeline of Half-Life, only a few hours before Gordon Freeman has teleported to Xen (an event that takes place in both Half-Life and Opposing Force). No explanation is given for the appearance of Race X aliens on Earth in-game, though the official strategy guide states that the race's intentions are to invade the planet to acquire its natural resources.

Pit Drone
Pit Drones are the first type of Race X aliens encountered in the game. They are short bipedal creatures with yellowish-tan skin and a small head which sports rows of sharp spines.

A Pit Drone's arms end in long scythe-like claws, which it can use to make vicious attacks. Fast and fairly intelligent, they tend to appear in groups of five or six, and are capable of making flanking movements and quickly surrounding their prey. They have two forms of attack: firing their head-spines when at long range, or charging towards the target to deliver a deadly slash with their claws. Some Pit Drones appear not to be capable of the head spine attack and, on closer inspection, have no spines in their head.

Shock Trooper
Shock Troopers are the most intelligent of the Race X aliens. Physically, they are humanoid with four arms and have a posture that makes them vaguely resemble Vortigaunts. Their bodies are covered in plate-like sections, similar in appearance to insect exoskeletons. Their skin is pale blue, and is not mottled or patchy like the skin of Xen creatures. They have a single large eye, whereas Vortigaunts have six. This eye is apparently part of a common morphology between Race X creatures - every Race X alien with a large eye (including the Pit Worm) has two eyelids which regularly blink horizontally across the eyeball and what appears to be "tentacles" surrounding their mouth (which is under the head).

Their primary weapon is the Shock Roach; a living creature, similar to the Alien Grunts' hive-hand. The Shock Roach fires bolts of electricity, which it constantly recharges on its own. The Shock Roach cannot survive without a living host for very long; if its Shock Trooper dies, it will detach itself and pursue a new host. If it nears a player that already has a Shock Roach, it will attack in a similar way to a headcrab before dying.

Shock Troopers also have the ability to regurgitate and throw spore grenades, which they tend to use against distant or concealed enemies. Infant Shock Troopers will forcibly launch the same type of spore when squeezed, and can thus be used as a Spore Launcher weapon. (The Spore Launcher is listed as "baby strooper" in the game's files.) In one of the Spore Launcher's idle animations in Opposing Force, it emits an amphibious purr.

Baby Shock Troopers are effectively tadpoles, an earlier stage that is only a head and torso, with tentacles trailing behind. Beyond the small size and lack of limbs, Baby Shock Troopers are also notable for having gills and two small eyes instead of the adults' single large one. They are amphibious, although immobile outside of water. Baby Shocktroopers are first found kept in a tank in the Sector E Biodome Complex of Black Mesa.

Shock Troopers are usually encountered in small groups, and often fight together with other Race X aliens, whom they seem to be allied with. Shock Troopers also possess a verbal form of communication, uttering strange electronic-sounding noises to each other. A skilled player can learn to recognize certain "phrases" muttered by a Shock Trooper prior to an attack and react accordingly.

Shock Troopers have mastered teleportation technology and use it to travel in and out of combat. They also control the teleportation of Pit Drones and Voltigore. It is interesting to note that at one point, the player observes a Shock Trooper grab a Black Mesa scientist prior to teleporting away; effectively kidnapping him.

Voltigore
The Voltigore, not to be confused with Vortigaunts, are gigantic and lumbering creatures serving as the alien race's heavy support infantry. Voltigore have four legs and two arms that end in scythe-like claws, and are distinguished by vivid purple stripes on their bloated carapace similar to those on a houndeye, though in a different color. These aggressive creatures use their innate ability to harness electrical charges to create a devastating ranged energy bolt attack, bearing some similarity to the Vortigaunt's green energy stream, although the Voltigore's energy attack is purple, and is much more lethal. At close range, they attack viciously with their claws. A player can recognize a Voltigore from afar by the unusual, electric-sounding bellows of the creature. When a Voltigore dies, its carapace explodes, causing massive damage to nearby creatures.

Baby Voltigore can be found later in the game. They are much smaller and weaker, lighter in color, and lack the energy attack. Baby Voltigore are only found in concealed underground nests and are closely guarded by the adults.

Pit Worm
Encountered in a sewage processing area in the lower levels of Black Mesa, this dangerous creature resembles an enormous caterpillar, and bears resemblances to the Gohma boss from the Zelda series. It makes bird-like vocalizations. Its segmented body supports a head dominated by a single large eye. This eye is the pit worm's primary weapon, capable of firing a searing energy beam at nearby enemies. If enemies get too close, the worm also has large claws to strike out with. If the worm is shot in the eye, it will recoil, shielding it with its claws for a few seconds before striking aggressively at the player.

The pit worm obstacle is similar to the tentacle sequence from Half-Life, in that the player cannot simply use his weapons to defeat the creature, but must use the surrounding environment. The process of destroying the pit worm requires the player to dissolve it by turning a valve and activating a gearbox, dumping toxic waste onto it - obvious references to Valve Software and Gearbox Software, the developers of Half-Life: Opposing Force.

Gene Worm
The Gene Worm is the final boss of Half-Life: Opposing Force, and the most mysterious of the Race X aliens. This life form is the equivalent of a "biological resource management factory." It's capable of taking any of Earth's natural resources and assimilating it to make them useful to the aliens' needs. If one fully entered Earth and became productive, it would effectively alter the planet enough to become useful as a new homeworld for Race X.

Physically, the creature resembles a green, worm-like creature with many tentacles, with a beak-like protrusion similar in both shape and position to that of the Xen tentacle. The Gene Worm attacks with its tentacles and also ejects a deadly biotoxin stream from its mouth. Its outer hide is impervious to damage; in order to kill it, the player must blind the creature by shooting both its eyes with the mounted laser guns on either side of the worm. This causes it to summon reinforcements by opening its abdominal cavity, revealing a portal orb that a Shock Trooper will teleport through. The player can inflict serious internal damage by firing at the orb.

The Gene Worm is found deep underground in a seemingly abandoned industrial area of Black Mesa, and appears through a portal opening in a room there, apparently either unwilling or unable to fully enter this world. The room itself has been fitted with mounted weapons which are powered by Xen energy crystals. The player character, Adrian Shephard, is sent down to the portal by a Black Mesa security guard, who remarks "Some of your buddies went down earlier, and I haven't seen 'em since." These soldiers were only able to manage to set up the mounted weapons before their unseen demise, although nothing is seen of their remains.

Sprite
Taking on the appearance of what looks like a flying ball of light, Sprites are creatures that can be seen floating through the facility several times during the game, becoming more and more frequent in later stages of the incident. However, they cannot be harmed and they do not hurt the player in any way. On occasions they even seem to be guiding Adrian. They eventually all lead to the portal that brings the Gene Worm in, possibly acting as energy conduits to construct and charge the gate that connects the two worlds. It is unknown if these are biological aliens or technological creations of Race X.

Tentacles (sometimes referred to as Giant Tentacles) are fictional creatures from the computer game Half-Life. They first appear in the Black Mesa Research Facility, where three tentacle creatures are growing inside a rocket propulsion test chamber. They reappear later in the game, including appearances on the surface and in Xen.

Appearance
Physically, the tentacles have a bizarre appearance. A large, green, segmented stalk supports a "head", which ends in a sharply pointed, bladelike appendage and features what looks like an eye. This "eye" appears to be a sensory organ, although the creature only reacts to sound and surface vibrations, implying that the race is blind. Tentacles usually need ome sort of liquid at their base to keep them alive. Tentacles also need to live in a pit or trench. They usually emanate from pits, into which they can retract when injured or in danger. Often they make long, low frequency vocalisations, that sound somewhat similar to the songs produced by whales.

Typically several tentacles use the same pit, suggesting that they may be appendages of a larger organism. Indeed in Half-Life, after the first tentacle encounter, the player travels through the chasm the creature had occupied. The tentacle's body encountered at the bottom of the chasm is somewhat squid shaped, with three stumps that appear to have been severed. Some concept art of the tentacle shows it to be cluster of three tentacles attached to a bulbous base, which matches that encountered in the game, this also suggests that the tentacles may in fact be a kind of Alien plant. Although tentacles usually come in groups or clusters of three, single tentacles are also encountered, and the number of tentacles present may reflect the size or stage of development of the base, or else a more spread-out being, with tentacles in various locales.

There is also a notable similarity between tentacles and the Gene Worm found in Opposing Force. Similar-looking smaller tentacles, with the same blade and "eye" have also been seen in the Metroid Prime series, often in holes in walls, retracting when injured in a similar manner.

Behavior
In terms of behavior, tentacles aggressively target prey in the immediate vicinity of their pits. While searching for prey, they gently tap the surrounding area, but when even the quietest noise or vibration is detected, the tentacles will furiously and repeatedly strike at the location where noise or vibration was detected. When a tentacle comes in contact with prey, it will attempt to pull it into the pit, presumably where it is consumed and digested. In the game, this behaviour is witnessed firsthand by the player when a scientist is grabbed and taken, screaming, into the pit at the base of the tentacles.

In the game, tentacles cannot be destroyed with the player's arsenal, but shooting the stalk a few times will temporarily drive the creature into its burrow. Great care must be taken when moving near them, forcing the player either to silently crouch past the burrow or cause a distraction with explosives (preferably hand grenades, as those don't reveal the player's location with sound), allowing the player to sprint out of range.

Half-Life 2
While Tentacles do not appear in Half-Life 2, pre-release gameplay videos showed an underground battle with a Hydra, a creature similar to a Tentacle, but with blue, glowing tentacles. The Nihilanth is the final boss in Valve's first-person shooter Half-Life. In the game, the Nihilanth is the controlling intelligence behind the invasion of Earth. Hovering silently in an enclosed cavern dozens of stories tall, it has been commanding the forces of Xen and holding open a dimensional rift connecting Xen to Earth, enabling its creatures to attack.

Physical Attributes
Physically, the Nihilanth resembles a gigantic, oddly-proportioned fetus with its head alone outsizing the rest of the body, and its brain cavity forming most of the head's bulk. Its legs, minuscule in relation to its body, appear either to be vestigial, or are the remains of amputation. The creature sits on a large mechanical levitating contraption consisting of a large base with spikes underneath. Like the rest of the intelligent Xen races, the Nihilanth has a third appendage protruding from the middle of its pectoral chest region. Its unusually long arms end in disproportionately huge hands and fingers, and it wears metallic wristbands, which look similar to bands worn by the Vortigaunts.

Attack Methods
The Nihilanth attacks by launching energy balls, which come in two types: a swarm of purple-colored electrical orbs that causes immense damage, and a slow-moving, green-colored orb (similar in appearance to the teleportation portals constructed in the Black Mesa Research Facility) which homes in on and teleports its target to other sections of its lair populated by Xen aliens. It also uses these green orbs to teleport Vortigaunts and other Xen creatures into its main chamber to help defend it against intruders. This may not be intended as the creatures appear only when the green orb flies into a wall or rock or is destroyed by the player and triggers the teleportation. A series of gold-colored "energy spheres" orbit around the Nihilanth's head, rendering it impervious to damage. These are consumed as the Nihilanth suffers damage from the player, but specialized crystals within the upper portion of its chamber replenish the spheres as they vanish. When the player destroys these crystals and does sufficient damage to its body so that all the "energy spheres" are consumed, the Nihilanth's head opens up like a flower, revealing a shining, massive portal as was described by the scientist who tasked you with taking it out (they were aware that this opposing portal was created by the intense mental strength of another being). Sufficiently damaging this portal destroys the Nihilanth. Additionally, once the Nihilanth uses up all its golden energy orbs, and cannot replenish them, it can only attack with one electrical orb, instead of a swarm of ten, or a teleportation orb.

Half-Life 2
The Ichthyosaur also makes a single appearance in Half-Life 2. During a teleport malfunction ("harmonic reflux"), Gordon Freeman is momentarily transported underwater, and is almost attacked by an Ichthyosaur before being transported elsewhere. Although this encounter is scripted, when an Ichthyosaur is spawned using console commands or a mod such as Garry's Mod it also attacks the player, suggesting that the developers planned on Gordon Freeman encountering them more than once.

Some implementations find that Ichthyosaurs are able to survive on land for limited periods before dying, but also show that they will actually drown if underwater for too long. This latter behavior may indicate that the creature was not fully implemented in the final game, although equally this may be a design feature as it is what might be expected from an air-breathing organism similar to dolphins, whales and even real ichthyosaurs. The latter interpretation is supported by the frequent surfacing of Icthyosaurs during the game (although this may simply be a ploy by the game designers to attract the player).

Most of the sound files associated with the Ichthyosaur contain the prefix "watery death" (the same prefix is used with files and sounds associated with the Carnivorous Leeches), suggesting that the designers may have originally intended the Ichthyosaur to serve the purpose of the Leech: to appear out of the foggy waters in the ocean, attack the player, and disappear in a similar manner; thus keeping the player out of deep water. Since the "watery death" and the Leeches themselves are included in a large trigger entity in the Valve Hammer Editor, using the Ichthyosaur in this fashion would have made an easy way to keep the player out of water, and may also explain the creature's lack of artificial intelligence. Though it doesn't aggressively attack the player, the Ichthyosaur may suddenly turn or nudge towards the player. It is actually easier to attack the Ichthyosaur, than to receive attacks from it. In order to be attacked by an Ichthyosaur, the player must be positioned directly in front of the Ichthyosaur's eyes. The Ichthyosaur attacks when the player is close enough so that he is not able to swim away without receiving damage. In the leaked beta of Half-Life 2 upon entering deep water no Leeches will appear, instead an Ichthyosaur will come and kill the player, but the Ichthyosaur is not visible. This Ichthyosaur will emit growls and such and sometimes will let out a high pitched noise that is similar to a Whale.

A Gonarch is a fictional creature in the 1998 first-person shooter computer game Half-Life. Only a single Gonarch is encountered by Gordon Freeman during the game. It is located within a chapter named "Gonarch's Lair" set in the border world Xen, and acts as a boss in a protracted battle that takes place in the closing stages of the game.

Description
Very little is known about a Gonarch's life cycle. What is known is that a Gonarch is the last stage of a female headcrab's life and that like most Terran non-human organism with a high mortality rate, very few female headcrabs reach this stage. While appearing very similar to a headcrab's anatomy there are a few differences. Gonarchs are supported by four razor sharp limbs. Standing at several meters tall, they dominate Gordon in size and power. Gonarchs are easily one of the largest and toughest known creatures from Xen. Heavily armored with an exoskeleton, they can take massive amounts of projectile and explosive damage, taking even more explosive damage to kill than a Gargantua. Because of this heavy armoring it is usually best to concentrate fire on the only unarmored part of a Gonarch, which is the large soft sac that hangs from the underside of the creature.

The large bag of flesh which hangs from the creature, commonly referred to as its "sac", seems to be a reproductive housing. During the battle with Gordon, it releases underdeveloped baby headcrabs at a rapid rate. These baby headcrabs, while mostly harmless, can be greatly troublesome en masse. Nothing is currently known about how Gonarchs reproduce. While Gonarchs appear to be mindless breeding machines, there is some evidence that they can feel emotion of some kind. When one of its offspring is killed, it will make an unusual and sad-sounding cry, suggesting it mourns for its dead young. Gonarchs are known to make other noises as well--most notably, when they are angry or injured, they will emit a loud cry, very similar to that of an elephant.

Entering a Gonarch's lair results in immediate attack, suggesting that they are highly territorial creatures, that they are highly protective of their young, or both. They attack by charging at their victim, then attempting to puncture them with their massive legs. They also have something of a ranged attack, by forcing yellowish balls of acidic material from the top of their shells, which they hurl through the air like mortars, raining down upon the victim. With all their traits combined, Gonarchs prove to be skilled at defending themselves and their young, and are one of the toughest enemies Gordon faces in Xen. Upon death, a Gonarch explodes violently.

Name
Within Valve Software, the creature is known as "Big Momma" (cf. its model name, ), a name that was given to it early on by staff developing Half-Life. Regarding the species name, one theory is that it is a portmanteau of the words "gonad" and "monarch". "Gonad" stems from the resemblance of the large sac that hangs beneath the Gonarch to a scrotum, while "monarch" references the Gonarch's role as a "king" enemy. This theory is supported by the book Half-Life 2: Raising the Bar, in which the following appears :

Half-Life 2
While the Gonarch is not encountered in Half-Life 2, an amputated part of it exists as an unused model a file in the leak version of Half-Life 2. This amputated part, essentially nothing but the sac that hangs beneath the Gonarch's body, is covered by many metallic supports (see here). It is likely that this model was created to explain how the Combine produce large quantities of headcrabs for use as weaponry. This fusion of living material with technology is entirely in keeping with the Combine forces that are encountered in Half-Life 2. The Gargantua, nicknamed "Garg", is a fictional creature from the 1998 computer game Half-Life by Valve Software.

The creature is approximately 4 metres tall, mostly blue in color, and has one yellow eye that glows red when it perceives a hostile unit. In place of hands, it sports two claw-like appendages which can be opened to emit jets of intense heat. Gargantuas can make loud roars that can damage structures. An example of the loud roars is in Half-Life: Uplink, near the ending sequence before the player gets trapped, the creature's loud roar made a vent collapse and the player is forced to go through and the next roar causes the vent to fall on to the platform the player gets stuck at in the start of the ending sequence. It can also send a shockwave towards its opponents by powerfully stomping the ground. This shockwave can also traverse vertical structures. The Gargantua moves fast and is very strong: it can smash or toss large obstacles from its path with ease. Gargantuas are very determined pursuers, and have been known to wait patiently for their target to come out of an area they can't reach for a considerable amount of time before moving on to do something else.

Gargantuas can be found on Xen, though their true origin is unknown. They share some physical characteristics with Vortigaunts, such as their backwards-jointed legs and hoofed feet. However, each Vortigaunt sports three arms (two at the shoulders and one jutting from the chest) while the Gargantua has four arms (two at the shoulder position and two spiked arms at the abdomen). Note that many of the species of Xen share common morphological characteristics.

The Gargantua is a kind of sub-boss creature. It is completely bulletproof, and requires a large amount of explosive, electrical, or energy damage before being destroyed. It is almost impossible to kill with normal bullets. Gargantuas can be seen in Half-Life in the chapters "Power Up," "Surface Tension," "Interloper," and "Nihilanth." In the Opposing Force expansion, a Gargantua can be seen in the chapter "Foxtrot Uniform" tied up on top of the hydroelectric dam, while marines and Race X Shock Troopers fight around and against it. In most of these locations, there is a convenient way to escape or destroy the Gargantua so that the player does not have to expend scarce ammunition on it, such as detonating explosives on it or calling in an airstrike against it. A Gargantua also appears during the final sequence of the Half-Life demo Uplink, where it kills several Black Mesa personnel before slowly heading towards the cornered player, at which point the demo ends.

Half-Life 2
In Half-Life 2: Raising the Bar, an early script for the beginning of Half-Life 2 mentions that "something that resembles the old Gargantua" was going to be seen from the train ride in the opening scene of the game. However, this introduction scene was heavily cut down throughout development, and the Gargantua is not in the final game.

Bullsquids are a fictional alien species in the science fiction computer game Half-Life. They are bipedal, highly aggressive creatures that appear throughout the Black Mesa Research Facility due to a dimensional rift. Bullsquids appear to be able to survive, if not thrive, in environments that are unfriendly or even toxic to humans, including sewers and pools of radioactive, chemical, or biological waste. In Xen, the border world from where they came (but to which they are not native), bullsquids are sometimes found near pools of an unknown liquid that has healing properties to humans. Note that the bullsquid is referred to as the Bullchicken in the console, i.e. "give monster_bullchicken"; this is probably because in the beta version and artwork they were named as such and remained like that, while their official name now is "bullsquid". Bullsquids are notably the first Xen lifeforms to be seen in the game, when Gordon Freeman is accidentally teleported to Xen for a few seconds.

Physical description
The body of a bullsquid is vaguely similar in appearance to that of a small theropod, with two short, muscular legs and a thick tail that tapers to a point. The thorax abruptly joins the creature's head with no neck or other visible separation. A typical specimen stands roughly one metre tall and about two metres in length. Two slit-pupiled eyes are mounted on either side of its head.

The bullsquid's most striking feature, however, is the collection of bright red, tentacular protrusions which surround its mouth and allow it to grasp prey. The tentacles are most probably red because bullsquids tend to eat human remains, covering the tentacles in blood. The bullsquid can also charge an opponent with surprising speed and force; these two attributes (tentacles and a tendency to charge) lend the creature its portmanteau name.

The bullsquid's overall coloration is roughly comparable to that of a spotted cat: its skin is a sandy brown covered on its upper surfaces with dark spots. The tail features a pair of prominent, outlined spots, one on either side, that are noticeably different than the dark spots on its back. These spots are similar in appearance to the bullsquid's eyes and may serve as a form of mimicry to confuse potential predators or lure prey much like the eyespots on various terrestrial animals. The creature's skin appears to be slimy, similar to that of a terrestrial amphibian such as a frog.

Bullsquids display a very territorial disposition, as they have often been seen attacking other creatures and even members of their own species. They viciously attacked headcrabs in Half-Life, usually not stopping until all headcrabs in the vicinity had been eliminated.

Although being intensely territorial, the bullsquid seems to be much more docile while in the border-world, or Xen, as seen in multiple areas in Half-Life and Half-Life:Opposing Force. When seen in the mysterious fluid that has such healing properties to Humans, the bullsquids do not attack, but just look on as you run by or kill them.

HD Pack Differences
The Half-Life High Definition Pack version of the bullsquid features a few key physical differences from the original version.


 * The tail has a hooked claw at its tip. This may have been introduced to explain the large amount of damage caused by the bullsquid's spin attack.


 * Each tentacle surrounding the bullsquid's mouth ends in a distinct sharp claw or perhaps more appropriately, "tooth", based on their white coloration.


 * The prominent "eyespots" on the either side of the tail are missing.


 * The eyes are black and glossy as opposed to white and relatively dull on the original version.

Offensive abilities
The bullsquid has an array of offensive capabilities: At close range, a hostile bullsquid will either maul its victim with its teeth, or suddenly spin around, delivering a powerful strike with its tail, often causing a gibbing. Additionally, the bullsquid is able to "spit" a toxic, bile-colored substance from its mouth. While not overly accurate, or fast, it causes moderate damage, even at very long range.

Half-Life 2
While not in Half-Life 2 itself, the book Raising the Bar explains that the creatures were, at least, going to be visible or mentioned during it. Dr. Eli Vance's lost leg was to be explained as a result of a bullsquid attack, and one of the scenes during a plot-reveal scene would have shown bullsquids frollicking outside a supermarket. In the leaked pre-alpha of the game, it seems that bullsquids were mainly intended to be fought underwater while swimming. Their skin color was changed to a deep maroon, while another alternate texture made them pale green.

Black Ops, sometimes hyphenated to Black-Ops, are a fictitious commando group briefly seen in the first-person shooter computer game Half-Life and later expanded upon and featured in its expansion pack Half-Life: Opposing Force. Working independently of the Hazardous Environment Combat Unit (HECU), Black Ops invaded the Black Mesa Research Facility to conceal any evidence of the resonance cascade.

Half-Life
Black Ops first appear in Half-Life during the chapter Apprehension, and later make one more appearance during the chapter Lambda Core. Only Female Black Ops are seen by Gordon Freeman in the game.

Female Black Ops are strikingly nimble and agile, able to sprint faster than any other enemy and can jump to extreme heights. They wear a black jump suit and use night vision goggles that include a headset with microphone, although none are ever heard speaking. They are armed with a silenced Glock 17 and grenades. At close range, they use an array of kicks to fight the player. When playing under the hardest difficulty level, female Black Ops have a cloaking field which they use to become invisible during combat, only revealing themselves when moving.

Female Black Ops were originally intended to be armed with crossbows as a weapon. The quivers they used to hold their bolts can still be seen on their belt in the final game.

The distinction between the Hazardous Environment Combat Unit and the Black Ops was not made at first in the original Half-Life. Although the two groups never encountered one another in the game, female assassins were coded to fight on the same side as the Marines. Many players assumed this meant they were working with the military since assassins had no backstory, and as such, many fan-made maps included them fighting alongside each other. It was not until the release of Opposing Force that more insight regarding the Black Ops was revealed.

Half-Life: Opposing Force
Black Ops are featured much more prominently as enemies in Gearbox Software's expansion pack Opposing Force. The reason for their presence at Black Mesa was also explained, something that was never made clear in the original game. Opposing Force explains that, after the initial failure of the HECU's clean-up operation, the Black Ops were sent to cover up the whole incident by destroying the entire facility. To do this, they intended to set off a thermonuclear device within the complex. Adrian Shephard locates the bomb the Black Ops delivered in a parking garage and is able to disarm it, but shortly thereafter it is seen being reactivated by the G-Man. The flash of a nuclear explosion is later witnessed, indicating the successful detonation of this bomb.

During gameplay, Black Ops are shown to have utter contempt for the HECU Marines, considering them incompetent and inept. One soldier angrily remarks to another, "Why do we always have to clean up a mess the grunts can't handle?" The Black Ops are hostile towards Marines, killing any who have not yet escaped as part of their mission. HECU radio traffic shows that the Marines were at first totally taken by surprise, much like how the HECU initially overwhelmed the Black Mesa personnel. Further evidence of their viciousness can be seen after discovering a Marine engineer who, after being brutally beaten and interrogated, is simply left for dead, trapped in a room by the Black Ops operators.

Along with the female Black Ops, Opposing Force introduced the group's male variant. Male Black Ops (also known as Male Assassins) wear black combat gear and ski masks that only expose their eyes. Some are seen wearing night vision goggles. Although not visible, they apparently have a communicator in their ear which they are seen listening to whenever they eliminate a target.

They are equipped with the same MP5 (M4A1 Carbine with the M203 grenade launcher in the High Definition Pack), but some male Black Ops have a M40A1 sniper rifle. Black Ops utilize equipment and vehicles, such as trucks and Apaches, similar to the HECU, but black in color (see also: black helicopters).

Black Ops soldiers can run much faster than the Marines, and up close, they use martial arts kicks and punches as melee attacks. Also, unlike their Marine counterparts, Black Ops operate in total silence when in combat, refusing to even yell in pain when injured.

Trivia

 * A characteristic given to the female Black Ops in the original Half-Life, one held to much amusement by fans, was a highly exaggerated bounce of the characters' breasts when she walked. This was removed in Opposing Force and in the PlayStation 2 console port of the original game.
 * Female Black Ops made a very small appearance in Half-Life: Decay's bonus mission "Xen Attacks", where they battle the players' two Vortigaunt characters in the same parking garage area that the Black Ops eventually place their thermonuclear device in. They do not appear within the main Decay missions themselves, however.

A Barnacle is a fictional alien species found in the Half-Life computer game series created by Valve Software.

Physical appearance and structure
Physically, barnacles resemble little more than a large mouth full of sharp teeth and a thin, but long and very powerful muscular hydrostat combining the functions of a tongue and tentacle, which can be retracted or extended to hang at near-floor level regardless of the animal's height from the floor. The creatures attach themselves to ceilings or the undersides of overhangs, from which they lower their sticky tongues. Although barnacles can be found in a wide array of environments, they seem to prefer damp areas. One curious point is that while many barnacles can be found infesting the Black Mesa Research Facility, fewer are encountered on the species' homeworld of Xen. This may be due to the fact that barnacles, like most (if not all) other cretures observed in Xen originated in another place and relocated to Xen.

Barnacles are relatively weak; a few shots from a 9mm pistol will kill them. They are easily dispatched from a distance, although players who become ensnared are usually able to kill them before being consumed. (This also allows the player to use the barnacle to rise through the room, e.g. to reach ledges.) The barnacles are weak against the crowbar, which in both games, kills them in a single hit. When killed, barnacles typically disgorge bones and other remains of recently-consumed victims.

In Opposing Force, a scientist refers to removing a barnacle from its "point of gestation". This suggests that a barnacle will naturally spend its entire life attached to the spot where it was born. However, it is unknown exactly how barnacles reproduce, or how the offspring spread to different environments and attach to ceilings. Real barnacles use mobile larval stages and the ocean to disperse, but no equivalent life history stage has been observed for Half-Life's barnacles (as a sidenote, the scientist's use of the term "gestation" may be incorrect depending upon how barnacles reproduce and disperse). However, it is known that they are attached very firmly and permanently, as evidenced by their continued attachment after death. In the Half-Life 2 series, the Barnacle has a "second mouth" that it uses to eat and when killed, the mouth hangs out from its actual body that can be seen at all times. This mouth is usually a lot more pink than the barnacle's original skin color.

Behavior
Barnacles are relatively simple creatures. They do not appear to possess any sensory organs (beyond the tongue's sensitivity to touch) and only a small degree of intelligence(if you feed them a random item from the ground, they will attempt to eat it once, but recognize it the next time, and ignore it.) - instead of actively hunting prey, they feed by reacting to external stimulus, in the form of animals which come into contact with the barnacles' tongue. Although the creatures do not demonstrate any intelligence in hunting, they possess an uncanny ability to attach themselves to ceilings overlooking thoroughfares frequented by potential prey, although some do seem to hide in corners far away from routes used by prey. Similarly to real barnacles, they typically occur in groups or colonies. These are found throughout the entire Half-Life series, and the player often encounters small areas populated with large numbers of barnacles, which do not seem to be in competition with each other.

Trapping and feeding abilities
When an object, living or otherwise, comes into contact with the tongue, it somehow grabs the object; the exact mechanism behind the tongue's stickiness is unknown, although Valve released a picture showing Gordon Freeman with a Barnacle's tongue wrapped around his neck and seemingly trying to strangle him. The barnacle then retracts its tongue, drawing the object towards its mouth. Upon reaching the mouth, the object is quickly evaluated by the barnacle: objects considered edible by the barnacle are crushed and consumed; inedible objects are released. Since Half-Life 2, it is noted that barnacles will raise their tongues to avoid inedibles that they have already dropped. Barnacles appear to be capable of killing and digesting a human being, stripping the skeleton of flesh and spitting out indigestible bones. As the barnacles are never seen moving, it can be assumed that their food requirements are relatively low and that they can survive for extended periods without food, perhaps explaining their sedentary lifestyle.

In the original Half-Life, humans become immobilised when caught by barnacles - although they struggle when wrapped in the creatures' tongues, captured humans appear to be incapable of fighting against the barnacle when they reach the mouth, even though they are clearly still alive. It is possible to save a NPC from a barnacle by killing it before he or she is consumed. The NPC will then simply drop, unharmed.

In Half-Life 2, barnacles take a few moments to differentiate between edible and inedible material. Consequently, objects such as tires, barrels or pieces of wood can be used to "distract" a barnacle and allow a player to easily slip past it. In a similar fashion, by setting alight an explosive barrel at the right moment or throwing a grenade at the tongue, a player can kill a barnacle attempting to eat it (or even several closely-placed barnacles). . It also seems that the Barnacle tries to wrap its tongue around the target tight enough to break bones and kill it. This is based on the observation that birds as well as Resistance or Combine troops die before they even reach the main body, merely by virtue of being caught. Turning on closed captions and then being captured by the barnacle reveals the sound file is called "Barnacle Neckbreak." Gordon Freeman is unaffected by the tongue's crushing attempts, probably due to his H.E.V. suit's neck-covering extension. An alternative explanation might be that tongue incapacitates the barnacle's prey by means of some poison. A third theory is that the barnacle snaps the spine of its victim which would explain why its prey doesn't fight back and dies before consumption and also why the "bone break" doesn't affect Freeman. It is interesting to note the manner in which a barnacle in Half-Life 2: Episode One deals with a Zombine (a transhuman Combine Overwatch soldier turned headcrab zombie): after capturing a Zombine, the barnacle will only eat the attached headcrab, while the beheaded body is dropped. On the other hand, barnacles have been recorded consuming the entire body of unaffected Combine soldiers. This could be considered evidence that barnacles dislike the taste of rotting or decomposed flesh, and would be consistent with their rejection of decomposed bodies thrown at them by the player.

Barnacle as a weapon
In the expansion pack Opposing Force, Black Mesa scientists have been able to successfully detach barnacles in good health, albeit with a high failure rate. The player can use a detached barnacle as either a weapon or as a grappling hook. Both functions take advantage of the affinity of their tongues for organic matter.

An Alien Grunt is a fictional creature from the first-person shooter computer game Half-Life created by Valve Software.

Description
The Grunts are known as the soldier class or creations of the humanoid Vortigaunt race of Xen. Tough, strong, and extremely hostile, Alien Grunts are armed with a biological weapon called the Hivehand, or Hornet Gun, which contains Hornets; insect-like flying creatures that seek out living targets and attack them. Hornets (also known to some as Thornets) respawn as an infinite supply of ammunition. The Grunt will also punch anything that gets too close with its thick bulky arms that end in blunt pincers. Alien Grunts share many features with their Vortigaunt counterparts: multiple red eyes, backwards-jointed legs, hoofed feet and a short arm extending from their mid-torso which is used for feeding. However, they do not seem to share the race's myriad energy-based powers, hence the need for the hivehand weapon. At one point in the game, a group of alien grunts appear to be commandeering, or at least have set up, an alien energy cannon, implying the necessary requirement of external weaponry. Grunts are equipped with metallic armour around the groin and shoulders, as well as metal helmets and shoes.

The Alien Grunts can be found being transported through a factory on Xen, stored in pod-shaped containers. The implication is that the Alien Grunts are manufactured beings, an idea that is substantiated by their shining, metallic armour that appears surgically attached. They are carried into combat zones through the use of Xen manta ships.

An Alien Controller (also known as a Xen Master) is an enemy which appears in the computer game Half-Life. Physically, the Controllers are small, levitating creatures, which closely resemble the Nihilanth. In Half-Life, they do not appear in the Black Mesa Research Facility until Gordon Freeman is about to teleport into Xen, but are more numerous in the alien world itself. They appear much more frequently within the complex in Half-Life: Decay during moments of increased displacement activity.

Description
The Controllers share many characteristics with the Vortigaunts, Gargantuas, Alien Grunts and especially the Nihilanth, suggesting that they are a related species. Like these other sentient creatures on Xen, the Controllers have a third vestigial arm growing from the center of the thorax. In addition to this, the Controllers have disproportionately large heads, which can peel open to reveal a (apparently mechanical) spike or cone. They attack by firing fiery spheres from their hands, in the same way as the Nihilanth. They can also fire an energy ball from their head that is larger, more powerful and has a slight homing ability. Although these attacks resemble flame, they are actually spheres of electrical energy, like ball lightning. Unlike the Nihilanth, the Controllers have long legs and are able to levitate without the assistance of a mechanical seat. It is unknown whether this ability stems from their strange psychokinetic powers, or from their seemingly mechanical parts.

During the Black Mesa incident on Earth, Controllers only appeared very rarely. As such, Controllers are found almost exclusively on Xen, usually encountered near places where Vortigaunts are made to work. Controllers seem to have an unspoken influence over the Vortigaunts, making them fight or toil at a whim. This might indicate that the Controllers share a limited version of Nihilanth's psychic enslaving power or act as an intermediary conduit, although their exact role in the hierarchy is unknown.

Antlions are a fictional insect-like alien species found in Valve Software's first-person shooter action computer game, Half-Life 2. They ended up on Earth after being transported from Xen by the portal storms, and adapted particularly well to their new environment. While they prefer sandy environments, these Antlions otherwise have little in common with real-life antlions, preferring to directly assault prey rather than passively trap them. Antlions appear starting in the Highway 17 chapter of Half-Life 2 and remain well into the Nova Prospekt chapter. They are a constant threat throughout Half-Life 2: Episode One, and the beginning of Half-Life 2: Episode Two prominently focuses on their nests.

Antlions
Antlions live in underground colonies, typically situated in sandy areas such as beaches. They usually hide under the sand, waiting for anything to venture near, at which point they quickly surface and tear it apart. Their aggression is not limited to humans or the Combine, and they will attack other xenofauna such as headcrabs. Antlions sense a victim's presence via vibrations transmitted through loose soil or sand. This makes it possible to safely venture through Antlion territories by walking solely over foreign items placed on the sand, or by walking across rocks. Once on the surface, Antlions can fly short distances to rapidly approach their prey. The Combine refer to Antlions as "virals," "biotics," or "exogens", as a soldier can be heard mentioning a "full biotic overrun" of the Nova Prospekt facility; however, the term biotic may also be a general term used by the Combine for any hostile life form, including Antlions and headcrabs.

In Half-Life 2, a swarm of five Antlions will usually emerge when the sand is disturbed. If the player is still on sand when one is killed, another will spawn to replace it. Half-Life 2: Episode One introduces the concept of Antlion burrows, essentially large holes in the ground from which Antlions spawn. Unless covered, burrows continually spawn Antlions to replace those killed. Refuge may be sought in water, since Antlions cannot swim and quickly drown when they come into contact with it. It is also possible to flip the Antlions over with a burst from the Gravity Gun, allowing for a quick escape. The Antlion group mentality makes up for their lower health totals: an individual Antlion is relatively easy to kill, but its friends will attack while the player is occupied. Antlions are the only enemies in Half-Life 2 that gib rather than becoming ragdolls if killed with a strong weapon.

The behavior of Antlions in respect to sound, vibration and aversion to water is analogous to that of Sandworms in the Dune universe. However, while the use of Thumpers to produce powerful vibrations attracts Sandworms, Antlions are repelled by the very same tactic, possibly experiencing sensory overload or pain in their presence, due to their sensitivity to vibration. Similar fictional creatures include the Graboids of the film Tremors, which react in a similar way to loud noises such as explosions, and the arachnid warriors in the film version of Starship Troopers.

Antlion Guards
Far larger and stronger, Antlion Guards (with the binomial name Myrmidont giganticus ) have command and control over other Antlions. Unlike the smaller Antlions, they cannot jump or fly, but make up for this by being much faster. Their primary attack is a charging head butt, which can also turn any loose objects within the Guard's line of sight into deadly projectiles if the Guard hits them.

While traveling along the coast, an encounter ensues with a Guard. After its defeat, a Vortigaunt extracts its pheropods and gives them to Gordon. To Antlions, the pheropods identify Gordon as a Guard and therefore do not attack. When Gordon encounters additional Guards later in the game, the Antlions under his command refuse to approach. The pheropods (called "bugbait" by the Rebels) can be used to send commands to the Antlions to follow Gordon by squeezing them or attack his enemies by throwing them. It's not clear where Gordon gets replacements, as the weapon has unlimited ammo. Combine Overwatch soldiers will flail about for several seconds if a pheropod is thrown directly at them, due to the powerful aromatic pheromones emitted upon contact.

As Gordon progresses into Nova Prospekt, a Combine Overwatch soldier can be heard saying, "Warning, primary target is, uh, engaged in, uh, command and control tactics with biotics. Repeat: Primary target has tactical C&C over biotics.", implying that Overwatch has never encountered a human utilizing the aid of Antlions before.

An image caption on the official Episode One site refers to an Antlion Guard seen in a screenshot as an "Ant Lion Queen", although it bears no difference in appearance from other normal ones (Alyx calls them Guards). Though this could simply be an error, it may indicate that this particular specimen is a female of the species, or that possibly all Antlion Guards are female. There is an unused alternate texture for the Antlion Guard in the Half-Life 2 and Episode One game cache files, giving the creature a blue-color skin. On the Valve developer wiki, it is referred as a "Cavern dweller".

In Half-Life 2: Episode Two, the player encounters an Antlion Guardian, which is a form of Antlion Guard that glows yellow/green and poisons the player upon contact, and when attacked at close range by the player (similar to the Antlion Workers). This neurotoxin effect is missing in the battle where the player takes on the Guardian and a Guard above ground later in the game; this is because this Guardian is merely a reskinned Antlion Guard, created by the developers so the player can "give a little payback to the creature that followed him through the caves." The player was not allowed to kill the Guardian in the previous mission, as the mission required it be alive. Episode Two also introduces a new effect for the Antlion Guards, causing them to bleed from their 'heads' when severely damaged.

Antlion Grubs
Antlion Grubs are apparently the larval form of Antlions, and were first seen in the leaked beta version of Half-Life 2. They were cut before the final release of Half-Life 2, but returned in Episode Two. Antlion Grubs glow, providing much of the light in the dark underground caverns, and die when stepped on. Upon death they drop a yellow blob that confers a small amount of health upon the player. Although they were originally designed to alert other Antlions when they were killed, this aspect was removed. However, a minor character does at one point suggest that stepping on Antlion grubs does attract the attention of Antlions. According to the Valve developer wiki, this was removed as it made players afraid to kill grubs for the health goo they dropped, making the cavern section of the game extremely difficult. In the Xbox 360 version of The Orange Box, the player can attempt to step on all of the Antlion Grubs in order to gain an achievment.

In their larval state, antlion grubs are docile and cannot harm the player in any way. They cling to nearly any hard surface, and feed off a substance which appears to be the same material that antlions build their nests out of.

Antlion Workers (Acidlions)
Antlion Workers or 'Acidlions' are similar to normal Antlions in terms of their legs and abdomen. They have a head similar to that of a termite, and possess small wings used for flying short distances.

Antlion Workers can spit toxic acid over long range, inflicting a large amount of splash damage. This may be an homage to the Bullsquid of the original Half-Life, which had a similar attack. Because they have a ranged attack, Antlion Workers typically do not engage in close combat, allowing standard Antlions to fulfill this role. However, they are capable of attacking the player with their legs at close range. Antlion Workers seen later in the game will normally be accompanied by normal Antlions; this may show some form of leadership role. They are more resilient than normal Antlions, and will explode into a spray of acid upon death that will damage anything in a small radius.

Antlion King
An "Antlion King" was touted in a few previews. It appeared to have a face resembling more of an alien, as it has few insectoid qualities. According to Half-Life 2: Raising the Bar, Gordon was supposed to fight one of these in a boss battle underground. However, as the above-ground levels gained more detail and the underground levels shrank, the decision was made to cut the Antlion King from the game. It may be the center of Antlion colonies if they are social creatures like bees or ants, but this is unlikely as the title of "King" suggests that this Antlion is male. However, Raising the Bar also indicates that the Antlions were to have a patriarchal society as opposed to a matriarchal one, possibly indicating that they mate in a different way than terrestrial insects. The Antlion King was originally to be fought in a large underground nest area with Antlions covering the walls and ceiling to such an extent that there was no room for the king. Raising the Bar contains a slightly comical comment from a Half-Life 2 game designer who tried to sculpt the Antlion King out of clay, which took many attempts to create without it collapsing. He also mentions that, for reference of scale, Gordon is stuck between the model's toes.

Defense
Along the coastline are areas protected by mechanical devices the Combine call Restrictors, dubbed "Thumpers" by resistance members. By repeatedly pounding the earth with metal beams, the vibrations produced deter the Antlions. Large-scale Restrictors appear around the perimeters of Nova Prospekt.

In Half-Life 2, stretches of beachsides devastated by Antlions prompted the Combine to set up Restrictors to combat the threat. Within City 17, the base of the Citadel functions as a massive Restrictor, operating constantly on the sides of the structure. This implies that Antlions have overrun much of the land. The destruction of the dark fusion reactor in The Citadel ceases most of the Citadel's functions, effectively nullifying the only defense City 17 had against an Antlion invasion. Antlion attacks in City 17 commence soon afterwards.

In Episode One, it is also revealed that it is possible to block Antlion burrows with large, heavy objects such as cars. Once blocked, Antlions can no longer emerge to the surface.

Reproduction
It is unknown how Antlions reproduce, but it is possible that they live in social colonies like bees or ants. This and the presence of a caste system are supported by the existence of Antlion Guards and the fact that Antlions commonly work together (another possibility would be that Antlions have an extreme form of sexual dimorphism). However, a resistance member also mentions in Half-Life 2 that the Antlions have a "spawning season". He could have been referring to adolescent females breeding with drones, however, Gordon only encounters one type of Antlion throughout the entire Highway 17 trip. This suggests that Antlions may be able to breed individually, as opposed to the colony theory. Additionally, some suggest that currently mating Antlions could be residing underground. They could also be independently breeding creatures that live in queen-less colonies. It should also be noted that Antlions have different yellow, black, or red markings and patterns. What relevance this has with creatures that are supposedly sightless is unknown, but it may be indicative of gender.

It needs to be pointed out that, as aliens from another dimension, there is no reason that Antlions would necessarily reproduce in a fashion similar to terrestrial organisms. It is possible that Antlions have three sexes, and Guards are a non-reproducing neuter sex whose only function is guarding nests.