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.
Kelpie (cailpeach) The water horse is a common form of the kelpie, said to lure humans, especially children, into the water to drown and eat them. It performs this act by encouraging children to ride on its back.