Caduceus is a continuation of the older Indo-European dragon-slayer motif. Wilhelm Heinrich Roscher (1913) pointed out that the serpent as an attribute of both Hermes and Asclepius is a variant of the "pre-historic semi-chthonic serpent hero known at Delphi as Python", who in classical mythology is slain by Apollo. One Greek myth of origin of the caduceus is part of the story of Tiresias, who found two snakes copulating and killed the female with his staff. Tiresias was immediately turned into a woman, and so remained until he was able to repeat the act with the male snake seven years later.
Vision Serpent meaning snake or serpent.). The Vision Serpent is thought to be the most important of the Maya serpents. "It was usually bearded and had a rounded snout. It was also often depicted as having two heads or with the spirit of a god or ancestor emerging from its jaws." During Maya bloodletting rituals, participants would experience visions in which they communicated with the ancestors or gods. These visions took the form of a giant serpent "which served as a gateway to the spirit realm." The ancestor or god who was being contacted was depicted as emerging from the serpent's mouth.