Coi Coi-Vilu or Caicai-Vilu/Cai Cai Vilu (from Mapudungun Kaykayfilu: Kaykay a name, and filu "snake") is the Mapuche god of water (or goddess, in some versions found in Chiloé) and, according to Mapuche myths (later also found in Chiloé), supreme ruler of the sea and of all sea-dwellers. This snake was a central figure in the Origin Of The Chiloean Archipelago. In Mapuche mythology, Coi Coi-Vilu is son of (a Pillan).