Nuckelavee

The Nuckelavee is the most monstrous and dreaded creature in the folklore of Orkney — a demon of the sea so horrible that even other spirits were said to fear it. It took the shape of a skinless horse-like beast fused with a rider that was part of its own body: a single great eye burning red, an enormous lolling head, and a man's torso whose arms reached almost to the ground — all of it raw red flesh and black blood coursing through yellow veins, with no skin to cover it. Its very breath blighted crops, sickened livestock and brought the wasting epidemic the islanders called mortasheen.

The Nuckelavee could not abide fresh water, and the one sure escape was to cross a running stream, which it would not follow. It was held in check only by the Mither o' the Sea, a summer spirit who confined it through the warmer months. The fullest account comes from the nineteenth-century Orkney folklorist Walter Traill Dennison, who gathered the tale from islanders for whom it was a living dread. Skinless, sea-born and pestilent, the Nuckelavee stands among the most genuinely frightening monsters in all of British and Irish legend.