Lyngbakr
Lyngbakr (Heather-Back) is the largest whale in Icelandic folklore, so massive that its back looks like a heather-covered island covered in soil, grass, and small trees. Sailors would land on what they thought was an island only to discover they had landed on Lyngbakr's back. When the whale submerged, the sailors would drown. Lyngbakr appears in Örvar-Odds saga and the Navigatio Sancti Brendani (Saint Brendan's Voyage). The name comes from lyng (heather) and bak (back). According to the legend, Lyngbakr is the second-largest sea creature after only Hafgufa. It feeds only once every three years