I had never heard of a Nix (aka Näck, among other variations) until I found Tiveden, but now I kind of want to make one into the main character of a story. (Or I would if I wrote fantasy of that kind. Orc Romance not withstanding.) The Nix is the Germanic water spirit, sometimes a merman but mostly a shape shifter, which puts me almost directly in mind of the river gods in Classical myth (especially the story of Poseidon impersonating the river god to get into Tyro's pants).
|The water-horse version of the Nix, with a boy|
Guys, I have not delved deeply into the research (wikipedia so far), but so far, I'm taken.
What's your favorite folklore-ish water-related creature?