Preserved in Snorri Sturluson's Skáldskaparmál (4) only, they deal with Thor's fishing expedition with the giant Hymir, where the god attempts to kill Jörmungandr.
The major sources for myths about Jörmungandr are the Prose Edda, the skaldic poem Húsdrápa, and the Eddic poems Hymiskviða and Völuspá.
Three myths are described in the twelve stanzas and half-stanzas of Úlfr's Húsdrápa: Baldr's funeral, Thor fishing for Jörmungandr, the Midgard serpent, and Heimdall's fight with Loki for the Brísingamen.
Jörmungandr, also known as the Midgard Serpent, is the serpent surrounding the Earth and grasping his own tail in Norse Mythology.
John Lindow suggests this is due to the large amount of time he spends in the realms of the jötnar, "who live on the other sides of boundaries", and points to a symbolic connection between jötnar and water, citing the ocean-dwelling Jörmungandr as an example.