(also known as Jörmungandr or Midgard Serpent)
The son of the fire god Loki and the frost giantess Angrboda, Jormungand is a large serpent. Odin threw Jormungand into the ocean and it grew so long it enciircled the earth, becoming known as the Midgard Serpent.
This 18th Century Icelandic manuscript shows Thor and Hymir fishing for Jormungand, the Midgard Serpent. The translated text reads:
Thor rows to sea with Ymir the giant and here
he's catching the Midgard Serpent. He gets angry
with Ymir and holds up the hammer Mjölnir and
wants to smite him for his cowardice as can be
read in the XIIth parable of Edda