Cirein Cròin is a sea serpent from Scottish highland folklore.
Etymology
Cirein Cròin may be translated from the Scottish Gaelic as "Grey Crest" but it is also known as Curtag Mhòr a' Chuain, "The Great Whirlpool of the Ocean", Mial Mhòr a' Chuain, "The Great Beast of the Ocean", and Uile Bhéisd a' Chuain, "The Monster of the Ocean".
Description
Cirein Cròin was believed to be the largest of all creatures and able to eat seven whales easily.
Stories
According to local folklore this serpent is able to take the shape of a little, silver fish when fishermen come into its territory. In this way, the monster avoids being sighted by them. Other versions say this monster becomes the small silver fish to attract the fishermen and make them catch it. It would then return to its original shape, eating the fishermen.