Kelpie, or water kelpie, is the Scots name given to a shape-shifting water spirit inhabiting the lochs and pools of Scotland. It has usually been described as appearing as a horse, but is able to adopt human form. Some accounts state that the kelpie retains its hooves when appearing as a human, leading to its association with the Christian idea of Satan as alluded to by Robert Burns in his 1786 poem "Address to the Deil".