the Midgard Serpent

In Norse mythology, Jörmungandr (Old Norse: Jǫrmungandr, pronounced [ˈjɔrmunˌɡandr̥], meaning "huge monster"[1]), also known as the Midgard (World) Serpent (Old Norse: Miðgarðsormr), is a sea serpent, the middle child of the giantess Angrboða and Loki. According to the Prose Edda, Odin took Loki's three children by Angrboða—the wolf Fenrir, Hel, and Jörmungandr—and tossed Jörmungandr into the great ocean that encircles Midgard. https://en.wikipedia.org/wiki/J%C3%B6rmungandr