See caption
Fishing boats in a storm on the surging sea, by Joseph Mallord William Turner, depicts the kind of sea conditions in which the marool might appear.
Source: Wikimedia Commons

The marool is one of the most malevolent of the monsters in the waters around the Scottish Shetland Islands.[1] It was described by the folklorist Jessie SaxbyAuthor and folklorist from Unst, one of the Shetland Islands of Scotland. She also had political interests and was a suffragette. in her Shetland Traditional Lore (1932) as a sea-devil in the form of a large fish, which appears particularly during storms when the sea foam is phosphorescent,[2] known as mareel:[3]

He had a crest of flickering flame, and eyes all over his head … He delighted in storm, and was heard to shout his wild exultant song when some luckless bark went under.[3]

References

  1. p. 281
  2. p. 226
  3. p. 140

Bibliography

Bane, Theresa. Encyclopedia of Fairies in World Folklore and Mythology. McFarland & Co, 2013.
Briggs, Katherine Mary. An Encyclopedia of Fairies: Hobgoblins, Brownies, Bogeys and Other Supernatural Creatures. Pantheon Books, 1976.
Saxby, Jessie M. E. Shetland Traditional Lore. Grant & Murray, 1932.