A kelpie is a scary fictional character, a Scottish water spirit that shifts its shape between a horse and a human. Kelpies are known for their love of drowning people.
For years, stories about kelpies have been used by parents as a way of warning children to be cautious around bodies of water. In some paintings of kelpies, they're pictured in human form but with hooves. Another kind of kelpie is the sheepdog breed which is associated with Australia, but which originated in Scotland and was named for the water spirit. The word comes from the Gaelic colpach, "steer or colt."