In Scandinavian myth, a water-monster that is part giantess. It lurks in stagnant pools and inland tarns of murky waters. Hafgygr is comparable to Grendel's mother in the Beowulf epic.
- Rose, Carol. (2000). Giants, Monsters, and Dragons: An Encyclopedia of Folklore, Legend, and Myth. New York: W.W. Norton & Company, Inc.