Jörmungandr

Jörmungandr (Old Norse - meaning "huge monster") is a giant sea serpent and one of the three children of Loki. According to the Prose Edda, Odin took Loki's three children by, the giant wolf Fenrir, the Norse Goddess of Death Hel, and Jörmungandr, and tossed Jörmungandr into the great ocean that encircles Midgard. The serpent grew so large that he was able to surround the earth and grasp his own tail. As a result, he received the name of the Midgard Serpent or World Serpent. When he lets go, the world will end.