Yig

Yig, a minor deity of the Cthulhu Mythos - known as the father of serpents -was long known as Bad Medicine, and quietly placated, by Native Americans. Yig is also alluded to throughout western American folklore.

Although Yig is easily placated, he is also easy to anger! Yig often sends his serpent servants to destroy or transform his enemies.

Source: The Curse of Yig, "Weird Tales", Vol 14, Number 5, Pages 625-36