Kelpie
Kelpie (#) , noun
[Compare Gael. cailpeach, calpach, colpach, a heifer, steer, colt, colpa a cow or horse.]
(Scotch Mythology) An imaginary spirit of the waters, horselike in form, vulgarly believed to warn, by preternatural noises and lights, those who are to be drowned. — Jamieson
Also: Kelpy