Jormungandr is one of three children born to Loki and Angrboda. He is depicted as a large serpent. The Gods were aware that he could cause much evil and harm to them and humans. So Odin decided to throw him into the sea, and he grew so large that he encircled the Earth easily. This is why he is known as the Midgard Serpent. He lies deep within the ocean, biting his own tail and anyone caught within his coils.
His rival is Thor, the god of Thunder, and two battles are recounted within the Eddas. In one, Thor is fishing to pull Jormungandr up. However he is stopped when Hymir, a giant, fears that this will cause Ragnarok and severs the line. When Ragnarok does occur, Jormungandr and Thor are destined to kill eachother. Thor manages to kill Jormungandr, but he has first bitten Thor, ending with both their deaths. There is also a story in which Thor must lift a colossal cat, which is Jormungandr disguised by Utgard-Loki's magic.
He is also known as Jormungand, The World Serpent, and The Midgard Serpent.
His herb is Willow.