The Leviathans are a Lovecraftian-like extra-dimensional race in the fictional universe of the Supernatural television series.
Leviathan predate the Angels, are a ravenously destructive race that sees other lifeforms as inferior, to be destroyed or treated as a food source. Immortals that are virtually indestructible, are able to fly, block angels' powers by their physical presence, regenerate from virtually any injury, are able to shapeshift, have enhanced senses, possess venomous blood that can kill angels, and have super strength, agility, and speed. Their true forms as perceived by humans is as that of balls of black goo with powerful jaws. When possessing human hosts, they dislocate the jaw displaying a forked tongue and large teeth. Their society is one with a hierarchy based on strength and fear, in which they betrayal is the norm and those whom fail or annoy others are eaten.