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.
Rainbow Serpent the concept of the Rainbow Serpent has existed for a long time in Aboriginal Australian cultures, it was introduced to the wider world through the work of anthropologists. In fact, the name "Rainbow Serpent" or "Rainbow Snake" appears to have been coined in English by Alfred Radcliffe-Brown, an anthropologist who noticed the same concept going under different names among various Aboriginal Australian cultures, and called it "the rainbow-serpent myth of Australia". It has been suggested that this name implies that there is only one Rainbow Serpent, when the concept actually varies quite a bit from one Aboriginal culture to another,