
1) Legendary serpent 2) Sea monster
Found on
https://www.crosswordclues.com/clue/jörmungandr

In Norse mythology, Jörmungandr (Jǫrmungandr, pronounced ˈjɔrmuŋɡandr̥), often written as Jormungand, or Jörmungand and also known as the Midgard Serpent ( Miðgarðsormr), or World Serpent, is a sea serpent, the middle child of the giantess Angrboða and Loki. According to the Prose Edda, Odin took Loki`s three children by Angrboða, the....
Found on
http://en.wikipedia.org/wiki/Jörmungandr

Norse Mythology) - AKA, the Midgard Serpent, offspring of Loki and Angrboða and archnemesis of Thor. When he lets go of his own tail the world will end.
Found on
https://www.tor.com/2012/08/13/sea-monsters-a-z/
No exact match found.