Another of the feared illhveli (a.k.a. evil whales) of Iceland is the Skeljúngur, meaning Shell Whale.
There a fundamental difference between this a all the other illhveli: the skeljúngur is safe to eat, even tasty, hence this is most dangerous of the edible whales cruising the Northern Seas. Moreover, even if catalogued as evil, the Skeljúngur has helped humans on occasion. Notably, a young skeljúngur aided Hjalmper and Olvir in their battle against a vicious hrosshvalur (i.g., Horse Whale).