Fossegrim

Fossegrim, also known simply as the grim (Norwegian) or Strömkarlen (Swedish), is a water spirit or troll in Scandinavian folklore. He is often depicted as a handsome, nude man playing the fiddle in streams and waterfalls. Fossegrim has been associated with a mill spirit (kvernknurr) and is related to the water spirit (nokken) and is sometimes also called näcken in Sweden.