Zoth-Ommog is the third son of Cthulhu in Lin Carter's Xothic Legend Cycle. He has a cone-shaped body, a razor-fanged reptilian head like that of a Tyrannosaurus rex, four broad, flat, starfish-like arms with suckers, and a mane of writhing tentacles.
He was imprisoned by the Elder Gods beneath the seabed near Ponape and R'lyeh. Like his brother Ythogtha, he is served by the yuggs and their lord Ubb, the Father of Worms, and is featured in Lin Carter's "Out of the Ages" (1975).