Nykurin
Nykurin is the Faroese nix, a dangerous freshwater shapeshifter. Appears as beautiful horse (nykur) on land; touching its tail sticks the victim as it drags them to watery death. Also appears as handsome youth luring women. Calling its true name 'nykur' breaks its power. Can become any quadruped except ram/lamb (cannot form horns).