Marine Animal Encyclopedia
Serpent Star Acanthaster planci
Serpent stars are a type of brittlestar with long, flexible arms. During the day they wind their arms tightly round the branches of the deep-water black corals in which they live. At night they uncoil their arms and move around, feeding on the living polyps of their host. A black coral bush one or two yards high may be host for up to forty or so serpent stars.