The Nuckelavee is a creature known from the Orcadian mythology that has the appearance of a horse-like demon and originating from the Norse mythology. Some of the earliest record of it originate from the 16th century. It’s believed that it’s name originates from the word “nuck” which means devil and the entire name means “Devil of the sea”.
Reports of people that have seen tend to vary a lot but they mostly say that it looked as if the torso of a man with a huge head (some say it looked like a rider while others described the creature to look more like a centaur) was fused with the body of a horse. A skinless, muscled, veins with black blood circulating and very long arms that drag on the ground. The creature had a single giant eye that seemed to be in flames.
The creature was one of the most terrifying things in Celtic folklore. So much that villagers were even afraid of whispering it’s name. And by researching it I can see why. The breath of the creature was believed to wilt crops, infect livestock with diseases and was believed to be responsible for countless droughts and epidemics even though it was believed that it was mainly a sea-dwelling creature.
It has been said that during the summer the creature is kept at bay by the mither of the sea (a creature that lives in the sea during the summer), but it roams free during the winter, infuriated by the smell of burning seaweed (which was used to create kelp at the time). The smoke of it was said made him enraged. The only way to escape it apparently was to cross a stream of water because of it’s intolerance of fresh water.