Ophiotaurus

 

The ophiotaurus was a monster who's front half was that of a bull, with a snake's tail replacing the back legs. It's only known appearance was from Fasti by Ovid. Although he's retelling a story from the lost Greek poem Titanomachia.

The ophiotaurus was a primordial being existed at the beginning of time when the world was forming. At that time animals were not fully formed and so had miss matched parts from the wrong species. The ophiotaurus, as well as the other first animals, were born from the goddess Gaia without a mate.

The bull was so toxic that its flesh could kill any being. If its entrails were burned (such as was done in ritual sacrifices) then the smoke would kill the gods. The bull was otherwise peaceful and not inclined to harm other creatures. Because of this the bull was trapped in a triple walled ring, within an endless dark forest, on the far side of the river Styx.

During the Titanomachy one of the titans' allies, either Briareus the Hecatoncheres, or Aigaion the giant, manages to find his way through the forest and scale the triple walls to the ophiotaurs. There he kills the creature and builds an altar to sacrifice it with the intent on killing the gods and winning victory for the Titans. Zeus sent a hawk to snatch the ophiotaurus's remains away before they could be burned. He then placed the remains of the ophiotaurus in the night sky as the constellations taurus and cetus, so the titans could never reach it again.