Ouroboros

The ouroboros or uroboros (/ˌjʊərəˈbɒrəs/; /ˌʊərəˈbɒrəs/) is an ancient symbol depicting a serpent or dragon eating its own tail. The ouroboros entered Western tradition via ancient Egyptian iconography and the Greek magical tradition. It was adopted as a symbol in Gnosticism and Hermeticism and most notably in alchemy. Some snakes, such as rat snakes, have been known to consume themselves.