She is so vast that she encircles the whole world and bites her own tail: Jörmungandr, the Midgard Serpent. Between her and the thunder god Thor reigns an ancient enmity – and at the end of the world the two kill each other.
Jörmungandr (‘great beast/staff’), also called Miðgarðsormr, is the middle of the three monstrous children of Loki and the giantess Angrboða – sibling of the wolf Fenrir and the death-goddess Hel. When a prophecy warns the gods of these children, Odin casts the serpent into the world ocean that surrounds the human world Midgard. There she grows – until she is so long that she encloses the whole earth and holds her own tail in her mouth. As long as she holds, the world holds.
The most famous encounter is told in the poem Hymiskviða: Thor rows out to sea with the giant Hymir, far beyond the usual grounds. For bait he takes the head of an ox, casts his line – and deep below the Midgard Serpent bites. A mighty struggle begins; Thor braces so hard that his feet break through the bottom of the boat. He hauls the monster up to the surface, eye to eye, and already raises his hammer. But at the last moment the terrified Hymir cuts the line – and the serpent sinks back into the deep. The fight is left undecided. For now.
“Then the worm-slayer boldly drew / the Midgard Serpent up to the gunwale.”after the Hymiskviða, translation after Karl Simrock / Bellows (public domain)
A second time Thor meets the serpent without knowing it. At the giant Utgard-Loki’s he must prove himself in trials. One of them: to lift a great grey cat from the floor. However hard Thor strains, he gets only one paw off the ground. Only later does Utgard-Loki confess the deception: the ‘cat’ was in truth the Midgard Serpent, and that Thor lifted it even a foot has shaken the giants to the core. One of the finest scenes of the Edda on how size and perception can deceive.
At Ragnarök the Midgard Serpent finally writhes onto land and spews venom over water and air; the sea floods the earth. Now comes the fated end of the old enmity. Thor slays Jörmungandr with the hammer Mjölnir – but the victory is deadly: poisoned by the serpent’s venom, the thunder god walks nine steps and then falls himself. Two old foes, one shared end.
“Hither there comes the son of Hlothyn, … / nine paces fares the son of Fjörgyn, / and, slain by the serpent, fearless he sinks.”Völuspá 56, translation after Henry Adams Bellows (public domain)
Thor · Fenrir, the wolf · Loki · Gotland’s picture stones · Ragnarök · The nine worlds · The Norse pantheon.
Poetic Edda (Codex Regius): Hymiskviða, Völuspá. Snorri Sturluson, Prose Edda / Gylfaginning (fishing trip, Utgard-Loki, Ragnarök), c. 1220. Picture stones: Altuna (Uppland, Sweden), Hørdum (Denmark). English public-domain translation: Henry Adams Bellows, The Poetic Edda (1923). Scholarship: Rudolf Simek, Dictionary of Northern Mythology; John Lindow, Norse Mythology (2001). Evidence and interpretation are kept apart.