Which giantess is the mother of the sea serpent Jörmungandr?

Angrboða is the giantess who is described as the mother of the sea serpent Jörmungandr.

In Norse myth, Angrboða is a jötunn associated with Loki. The Prose Edda identifies her as the mother of three formidable children: Fenrir, Jörmungandr, and Hel. Jörmungandr became the Midgard Serpent, an enormous creature cast into the ocean surrounding the human world.

The serpent grew until it could encircle Midgard and grasp its own tail. Its release is one of the signs of Ragnarök, the catastrophic final conflict. Jörmungandr is especially linked with Thor: in one famous episode, Thor nearly catches the serpent while fishing, and at Ragnarök the two enemies finally fight. Thor kills Jörmungandr but dies shortly afterward from the serpent’s venom.

A common mix-up is to treat Hel as Jörmungandr’s mother; Hel is instead his sister. Angrboða’s name is often translated as “she who brings sorrow” or “harm-bidder,” fitting her role as the mother of Loki’s monstrous offspring.