Ophion  a snake
 
Primordial snake or World Serpent. Ophion was a snake created by Eurynome, who rolled the air and winds into a living being.

According to the Argonautica, Apollonius of Rhodes wrote a very brief account of the Creation that was very different from Hesiod in Theogony. He replaced Uranus and Gaea with Ophion and the Oceanid Eurynome.

Ophion was an obscure god, who was only recorded in the Argonautica. So nothing is known about him in other sources. It seemed that Ophion might have being the first primordial god. Eurynome, however, was known as the daughter of Oceanus.

When the sky, earth and sea were created, and the creatures began to populate the world, Ophion and Eurynome ruled from Olympus. The Titans rebelled against their rule, where Cronus and Rhea threw Ophion and Eurynome out of heaven, into the river Oceanus. Cronus and Rhea then ruled the world in their places. They ruled while Zeus was still a child living in the cave of Mount Dictye, and only until the Cyclopes wield and gave the thunderbolts to Zeus.

As I had said, Apollonius' account is very short about Eurynome and Ophion (See Apollonius' Account in the Creation page). I had to look elsewhere on this strange creation myth.