Jormungand is a dragon from Norse mythology, better known as the Midgard Serpent. Which in Norse mythology plays a role in Ragnarok, the apocalypse. The Marvel adaptation was created in 1966 by Stan Lee and Jack Kirby. Making its first appearance in issue #127 of the 1st volume of the Thor comic book series.
Jormungand (aka, the Midgard Serpent) is a descendant of Set, an Old One. It is the offspring of Set's great granddaughter, the giantess Angerboda who mated with the Asgardian trickster god Loki. The Midgard Serpent is an incomprehensibly large serpentine dragon, which is able to wrap itself around Earth.
It exists in ethereal form around the planet, and when it squeezes the world it causes natural disasters such as earthquakes and storms. When manifesting itself in physical form, time freezes on the planet, with only godling races like the Asgardians being unaffected.