Jörmungandr

Jörmungandr, the "Midgard Serpent" or World-Serpent, is the child of Loki and Angrboda, cast into the ocean by Odin, where it grows so vast it encircles the entire earth and grasps its own tail. At Ragnarök it erupts from the sea to fight Thor, and their mutual killing is one of the most famous deaths of the end.

The casting out

In the Prose Edda, Odin takes Loki's three monstrous children, Fenrir, Hel, and Jörmungandr, and disposes of each. He flings the serpent into the deep sea surrounding Midgard (the world of humans), where it grows until it can encircle the whole earth. There it lies, an ambient threat beneath the waves, the boundary of the known world made flesh.

The fishing and the end

Two episodes define the serpent's relation to Thor. In one well-known myth, the god and the giant Hymir go fishing; Thor baits his hook with an ox head, and Jörmungandr takes it, surfacing in a storm of fury. Thor raises his hammer to crush the serpent's head, but the giant cuts the line in terror, and the serpent sinks back, the confrontation deferred. At Ragnarök the deferral ends: Jörmungandr releases its tail, floods the land with the sea, and meets Thor. Thor kills the serpent with Mjölnir but is poisoned by its venom and takes only nine steps before dying.

The World-Serpent is the encircling boundary, the Ouroboros of the Norse cosmos, and its rising is the sea itself becoming the end. Like Fenrir and Surtr, it is a force the gods could not finally contain, only postpone, and its death-dealing is mutual: the world's edge and its great defender fall together.

The sources give the serpent a biography. Cast into the sea by Odin as a child, it grew in the outer ocean until it encircled Midgard and grasped its own tail; the gods' act of containment was itself the making of the world's edge. Thor's encounter with it is not confined to Ragnarök: the poem Hymiskvida shows the fishing expedition in which Thor hooks the serpent with an ox-head bait and nearly hauls it up, only for the giant Hymir to cut the line in terror, with some versions adding a blow to the skull that the serpent survives. Snorri reads that encounter as the gods' last successful postponement.

Iconography carries the myth back centuries before the texts: the Altuna stone in Sweden shows Thor fishing with the serpent below his boat, and the Gosforth Cross pairs the same scene with other Ragnarök images. The material is thus among the best-attested of the Norse figures, carved from perhaps the tenth century and written down in the thirteenth.