Jormungand – The Midgard Serpent
The son of the fire god Loki and the frost giantess Angrboda, Jormungand (also known as Jörmungandr or Midgard Serpent) is a large serpent. Odin threw Jormungand into the ocean and it grew so long it encircled the earth, becoming known as the Midgard Serpent.
At Ragnarok, Jormungand was slain by Thor, but first bit the god. His venom eventually killed Thor.