Jormungand

Jormungand in Norse mythology, was the Midgard-snake, the daughter of Loke and the giantess. Angerbode, also the sister of the wolf Fenris and the blue Hela. The gods threw Jormungand into the ocean, where she grew so as to encircle the earth. When she drinks, there is low tide; when she gives back the water again, it is high tide. Thus she will live until Ragnarokr (world's end) comes. Thor will then slay her with his miolner, or hammer, but will himself be drowned in the poisonous streams issuing from her mouth.