Huldra. A hulder is a seductive forest creature found in Scandinavian folklore. A multitude of places in Scandinavia are named after the Hulders, often places by legend associated with the presence of the "hidden folk".
Kelpie -- The Kelpie is a supernatural water horse from Celtic folklore. They tend to be malevolent in nature. They are able to transform (usually into beautiful women) and lure victims into the water to drown them.