The Ouroboros or Uroborus is an ancient symbol depicting a serpent or dragon swallowing its own tail and forming a circle.

The Ouroboros often represents self-reflexivity or cyclicality, especially in the sense of something constantly re-creating itself, the eternal return, and other things perceived as cycles that begin anew as soon as they end. It can also represent the idea of primordial unity related to something existing in or persisting from the beginning with such force or qualities it cannot be extinguished.