What shape-shifting water spirit lures people to drown in Scandinavian folklore? The answer is Nøkk.
The Nøkk is a dangerous freshwater spirit of Scandinavian folklore, known by related names such as Swedish Näcken and Norwegian Nøkken. Stories place it in lakes, rivers, streams, and waterfalls, where it uses music, beauty, or disguise to draw people toward the water. Its victims may be pulled under or lured into drowning.
Shape-shifting is central to the tradition. The spirit may appear as a handsome musician, an old bearded man, an animal, or a horse—often a striking white or black water horse. In some accounts it takes the form of an inanimate object or treasure, turning curiosity into a trap.
The Nøkk is often presented as purely evil, but folklore is more varied. Some stories say it can teach exceptional music to a respectful visitor or live peacefully with a human for a time. The creature is also related to the wider Germanic nixie tradition, but it should not automatically be equated with the modern mermaid, kelpie, or selkie.