Nokken or Puken as it is sometimes called, is a dangerous and manipulative creature from Norwegian folklore. The word nøkk comes from Old Norse which means seahorse.
It wanders in rivers, small waters, and seas.
I’m the Myths and Legends
In the stories, they live in waters with water lilies, so it would be easier to attract people near the water, especially children who wanted to collect the lilies. Nokken is a shapeshifter, for women he becomes a handsome young man with a violin, which he uses to play beautiful, seductive music, to attract women closer.
Another form is that of a beautiful white horse with opal black eyes, the horse's mane almost like thick fog and it would shine with a white radiance. Nokken could also transform into an old wooden ship or an old tree trunk.
However, his true appearance is horrible, as he is covered in moss and his eyes are bright yellow. It has a large mouth with sharp teeth, and its skin is like that of a drowned man, who has been underwater for a long time. It is said that if one is captured by Nokken, his name must be said and he will disappear into the waters again.
Or that you could also try to appease him by bringing him a gift that could be three drops of blood, a bottle of Vodka or snus (wet tobacco), then he will change his attitude and perhaps I taught you to play his melodies.