Snakes are my least favorite of all of the Big Guy's creations. But rather than wax on about that, which I will leave to someone else (surely i have a fellow ophidiophobe on the blog?) I'd like to bring up a far more fascinating reptile, the ouroboros. This mythological fellow *can* be a snake or serpent, but he can also be a dragon - as long as he eats himself.
If the idea of self-cannibalism repulses you, you will probably be startled to know that most of us practice autophagy when we're in a state of extreme hunger. Our cells, it appears, have no qualms about consuming themselves.
All in all, this is heavy stuff. Ouroboros exists in some form in many cultures' mysthology. In addition to being said to represent the natural cycle of life and death, spiritualists add resurrection into the mix, and philosophers and Freudians also have give the subject attention. It wouldn't be going too far to say that it's a persistent symbol everywhere, which to me makes it excellent fodder for fiction.
I'm trying to cook up a short horror story idea that uses this in a subtle fashion. (While my more recent books have been called "gory" by some, I like to think that I have a light touch with visceral detail, and use suggestion as a more interesting tool.)