In Scandinavian folklore, the fossegrim, also known simply as the grim (Norwegian) or Strömkarlen (Swedish), is a water spirit or troll who plays the fiddle, especially the Hardanger fiddle, and can be induced to teach the skill.
The fossegrim is related to the neck or nixie and is sometimes also called näcken in Sweden, but is associated with rivers (the Swedish name "Strömkarlen" means "The River Man") and particularly with waterfalls (foss in Norwegian) and mill races. He has been associated with the kvernknurr, a mill spirit.
The fossegrim is described as an exceptionally talented fiddler: the sounds of forest, wind and water play over his fiddle strings. The Swedish strömkarl's lay is said to have eleven variations, the final one being reserved for the night spirits because when it is played, "tables and benches, cup and can, gray-beards and grandmothers, blind and lame, even babes in the cradle" will begin to dance. The fossegrim is said to be willing to teach away his skills in exchange for a food offering made on a Thursday evening and in secrecy: a white he-goat thrown with head turned away into a waterfall that flows northwards, or fenalår (smoked mutton) stolen from the neighbour's storage four Thursdays in a row. If there is not enough meat on the bone, he will only teach the supplicant how to tune the fiddle. If the offering is satisfactory, he will take the pupil's right hand and draw the fingers along the strings until they all bleed, after which he will be able to play so well that "the trees shall dance and torrents in their fall stand still". Jacob Grimm cites a variant in Johan Ödman's 18th-century Chorographia Bahusiensis according to which the strömkarl must be offered redemption or he will merely break his instrument and weep bitterly.
Famous fiddlers who were said to have learnt from the fossegrim include Torgeir Augundsson, known as Myllarguten (who denied it to Theodor Kjerulf) and Ole Bull, whose statue in the centre of Bergen depicts a fossegrim playing his harp under the falling water; the sculptor, Stephan Sinding (1846–1922), intended it to symbolise his being inspired by Norwegian nature and folklore. The folklorist Rikard Berge said that he told the story to the fiddler Håvard Gibøen when they were both boys but that neither believed it.
- Benjamin Thorpe, Northern Mythology: comprising the principal popular traditions and superstitions of Scandinavia, north Germany, and the Netherlands, 3 vols. London: Lumley, 1851–52, OCLC 656592812, Volume 2 Scandinavian Popular Traditions and Superstitions, p. 23.
- Eugen Mogk, Mythologie, Grundriß der germanischen Philologie 1, Strasbourg: Trübner, 1891, OCLC 162976637, p. 1028 (in German) equated them, but Reimund Kvideland and Henning Sehmsdorf, Scandinavian Folk Belief and Legend, Nordic Series 15, Minneapolis: University of Minnesota, 1988, ISBN 9780816615032, p. 248, distinguish the "mill sprite" as a mischievous creature who punishes grinding on Christian holy days.
- Jacob Grimm, Teutonic Mythology, 4th ed. tr. James Stallybrass, Volume 2, London: Bell, 1883, OCLC 457311367, pp. 492–93.
- Jacob Grimm, Teutonic Mythology, p. 493.