Fenrir

The wolf, son of Loki and the giantess Angrbotha, brother of the Midgard serpent; he bit off Tyr's right hand and waits in fetters "By the mouth of the river" until Ragnarok, when the fetters burst, he swallows Odin and is torn apart by Odin's son Vithar; a brood of wolves sprung from him steals the sun and the moon.