Jormugandr is one of Loki's children in Norse mythology and a major player in the events of Ragnarök, which was the Norse version of the End Times (though unlike monothestic faiths Ragnarok was seen as the end of a cycle rather than time itself, with a new world destined to be born from the old world's destruction). He was cast into the ocean as an infant for the crimes of being a serpent and being destined to help kill the people who cast him into the ocean.
Jormugandr was one of the apocalyptic beasts who would lay waste to the current world and help in killing off the current gods (known as the Aesir), though would also be slain in the process, allowing for new life to eventually form from the ashes of the old.
Jörmungandr is the son of Loki and Angerboda, a giantess who was counted among his wives. Realizing the peril Jörmungandr could place Asgard in, Loki's father Odin banished Jörmungandr to the depths of the oceans of Earth.
The prophetess Volla prophecized that at the time of Ragnarok, the Midgard Serpent would be slain by Thor in battle, but then Thor himself would perish by the serpent's venom.
While in the court of Utgard-Loki, Thor was challenged to lift his cat off the ground, but was humbled when the cat managed to keep at least one foot on the ground at all times. Utgard-Loki then revealed his so-called cat was actually the Midgard Serpent in disguise.
Thor went fishing with an ox-head on the boat of the giant Hymir for the Midgard Serpent. Thor succeeded in catching the serpent, but Hymir grew afraid and cut the line believing he was saving Thor from himself. As the serpent retreated, Thor grew angry with Hymir and struck him. He then departed under the power of his hammer as he told Hymir he ought to be grateful that he was letting him live.
- Jormugandr is a popular Norse monster, though ranking below his siblings Fenrir or Hel as well as his infamous father Loki - nevertheless the "World Serpent" is a common and frequently seen antagonist in many modern takes on the Norse myths, some of the most popular of which include:
- Marvel Comics, who adapted Thor into a superhero franchise, has depicted Jormugandr as a recurring foe to Thor - both in original comic book format and in more recent cartoons.