He could go from snake to man and back again at will. Oddly, he was married to a mortal woman who cheated on him with another snake man. She was obviously into snakes in a big way. In revenge he hid in a log, — or it may have been a primitive drum — and bit her.
It’s all tied up with fertility and initiation rites which are beyond our comprehension. We could explain the whole thing involving DREAMTIME, but we are going to have an early night.