The user is or has the ability to take on the form of Nguruvilu (lit. "fox snake", also: Guirivilo, Guruvilu, Ñuruvilu, Ñirivilu, Ñivivilu, Ñirivilo o Nirivilo), a creature found in the Mapuche mythology of Chile. They are river-dwelling creatures that look much like a fox with a long snake-like body and a long tail with fingernails that it uses like a claw.