Näcken

The Näcken (Swedish) or Nøkk (Norwegian/Danish) is one of the most feared water spirits in Scandinavian tradition. He dwells in lakes, rivers, and waterfalls, particularly deep pools. He is master of music — his violin-playing is so beautiful it cannot be resisted — and uses it to pull listeners into the water. He could be contracted to teach violin in exchange for offerings, but the price was dangerous.

Most commonly a beautiful, pale-skinned young man, naked or in fine clothing, playing a violin while sitting on a rock in the water. He could also appear as a white horse standing in shallow water (an invitation to ride him to drowning), or as a piece of driftwood. Water dripped constantly from his clothing and hair.

His music was irresistible — those who heard it would dance until they dropped dead, or wade into the water to be drowned. Could shape-shift into a horse, a man, or floating debris. Masters musicians who made contracts with him gained supernatural skill. Could control the currents of rivers.