The Kelpie is a supernatural water horse from Celtic folklore that is believed to haunt the rivers and lochs of Scotland and Ireland; the name may be from Scottish Gaelic cailpeachor colpach "heifer, colt".
In mythology, the kelpie is described as a strong and powerful horse. It is a white and sky blue colour and appeared as a lost pony, but could be identified by its constantly dripping mane. Its mane and tail are a bit curly. Its skin was said to be like that of a seal, smooth but as cold as death when touched. Kelpies were said to transform into beautiful women to lure men into their traps. They created illusions to keep themselves hidden, keeping only their eyes above water to scout the surface.
The fable of the kelpie varies by region. The Kelpie's mane is said to be a sky blue colour. The water horse is a common form of the kelpie, said to lure humans into the water to drown them. The water horse would encourage people to ride on its back, and once its victims fell into its trap, the water horse's skin would become adhesive and the horse would bear the victim into the river, dragging them to the bottom of the water and devouring them—except the heart or liver. A common Scottish tale is the story of nine children lured onto a kelpie's back, while a tenth kept his distance. The kelpie chased the tenth child, but he escaped. Another more gruesome variation on this tale is that the tenth child simply stroked the kelpie's nose but, when his hand stuck to it, he took a knife from his pocket and cut his own hand off, cauterizing it with wood from a nearby fire.
There are many mythological creatures similar to the kelpie, such as the "nuggle" from Orkney, and a "shoopiltee," or "njogel," or "tangi" from Shetland. On the Isle of Man, the kelpie is known as the cabbyl-ushtey (Manx Gaelic for "water horse", compare to Irish capall uisce) or the glashtin. In Wales, a similar creature is the Ceffyl Dŵr. It also appears in Scandinavian folklore, where it is known by the name Bäckahästen, the brook horse. In Norway it is called nøkken, where the horse shape is often used, but is not its true form. In the Faroe Islands it is called Nykur and in Iceland nykur or nennir. Another similar water horse appearing in the mythology of Scotland and Ireland is the each uisge, "a sea-dwelling creature that often takes the form of a handsome man. In Greek mythology, Poseidon is the god of the oceans and of horses, and took the form of a horse to seduce Demeter.