Hafgufa

Hafgufa (Old Norse: haf "sea" + Old Norse: gufa "steam"; "sea-reek"; "sea-steamer") is a sea creature, purported to inhabit Iceland's waters (Greenland Sea) and southward toward Helluland. Although it was thought to be a sea monster, research suggests that the stories originated from a specialized feeding technique among whales known as trap-feeding.

The hafgufa is mentioned in the mid-13th century Norwegian tract called the Konungs skuggsjá ("King's Mirror"). Later recensions of Örvar-Odds saga feature hafgufa and lyngbakr as similar but distinct creatures.

According to Norwegian didactic work, this creature uses its own vomit-like chumming-bait to gather prey-fish. In the Fornaldarsaga, the hafgufa is reputed to consume even whales or ships and men, though Oddr's ship merely sailed through its jaws above water, which appeared to be nothing more than rocks.