Siyokoy (Philippine mythology)

In Philippine mythology, a siyokoy (also syokoy) is an aquatic humanoid creature often described as having scales, webbed limbs, and fins. Most legends characterise siyokoy as hostile to humans, and are said to drown individuals.

While siyokoy are often likened to the Western mermaid due to the Philippines' colonial history, its name suggests a Chinese origin. This is highly plausible given Chinese records of indigenous polities in what is now the Philippines dates to at least 982 AD, several centuries before Europe’s Age of Discovery.

Etymology
The term siyokoy came from the Hokkien shui gui. In Chinese folklore, shui gui are the restless spirits of drowned people, who drag unsuspecting victims underwater and drown them in order to possess their bodies.

Defining characteristics
Compared to sirena and kataw that have more human features, siyokoys are animalistic in form and structure. Some describe siyokoy as:

"...horrifying sea creatures with fish-like bodies and long green tentacles. They drown mortals and eat them. They have gill slits, are colored brown or green, and have scaly skin, comparable to that of fishes."

Predatory or potentially toxic animals such as eels, octopus, rays, and squids are common companions of siyokoy.