Definitions for "Fossegrim"
Also known as a "neck", the term describes a river spirit which takes the form of a ghostly youth, sometimes reported to be sighted seated in the middle of a stream, entertaining himself with playing a harp. The spirit is reported to be harmless, although it can be cruel to young women who are fickle in nature with their affections. In some parts of Europe, superstition holds that carrying an unsheathed knife while in a river-borne boat will "bind the neck". Also see "kelpie".
In Scandinavian folklore, the fossegrim (plural fossegrimen) is a supernatural spirit or troll said to live under a waterfall (foss). He is known to be an exceptionally talented Hardanger fiddle player who plays all sounds of nature. The sounds of forest, wind and water play over his fiddle strings.