Jörmungandr

According to the Prose Edda, Odin took Loki's three children by Angrboða – the wolf Fenrir, underworld ruler Hel, and the serpent Jörmungandr – and removed them from Asgard (the world of the Æsir).

[2] The word "gandr" can mean a variety of things in Old Norse, but mainly refers to elongated entities and or supernatural beings.

Gandr can refer to, among other things: snake, fjord, river, staff, cane, mast, stem, branch, penis, bind, and the like (mainly in a "supernatural" or "living" sense).

Útgarða-Loki later explains his deception and that Thor's lifting the cat was an impressive deed, as he had stretched the serpent so that it had almost reached the sky.

[7][8] The Eddic poem Hymiskviða has a similar ending to the story, but in earlier Scandinavian versions of the myth in skaldic poetry, Thor successfully captures and kills the serpent by striking it on the head.

[10][11][12] Many of these depictions show the giant cutting the fishing line; on the Altuna stone, Thor is alone, implying he successfully killed the serpent.

If the stone is correctly interpreted as a depiction of this myth, it would indicate that the story was preserved essentially unchanged for several centuries prior to the recording of the version in the Prose Edda around the year 1220.

[13][9] As recounted in Snorri's Gylfaginning based on the Eddic poem Völuspá, one sign of the coming of Ragnarök is the violent unrest of the sea as Jörmungandr releases its tail from its mouth.

[1] It will advance, spraying poison to fill the air and water, beside Fenrir, whose eyes and nostrils blaze with fire and whose gape touches the earth and the sky.

[18] An alternative analysis of the episode by Preben Meulengracht Sørensen is that it was a youthful indiscretion on the part of Thor, retold to emphasize the order and balance of the cosmos, in which Jörmungandr played a vital role.