The surviving accounts vary, with some storytellers merging the two monsters so that rider and horse become one - a vile hybrid of man and beast that, they swore, was Nuckelavee's true shape.
From the few recorded descriptions of the Nuckelavee, we learn that his head was similar to that of a man only "ten times larger". He had an incredibly wide mouth that jutted out like a pig's snout and a single red eye that burned with a red flame.
Hairless, his body was also skinless, its entire surface appearing like raw and living flesh. It was said that his thick, black blood could be seen coursing through his veins, as his sinewy muscles writhed with every movement he made. His long ape-like arms hung down to the ground and from his gaping mouth spewed a foul, black reek.
All in all, not a pleasant sight to encounter on some lonely stretch of coastline.
Nuckelavee illustration commissioned by Colin Stuart (C) 2018.
Like fridge-light horror.
Because, goodness, the Nuckelavee is pretty unnerving, with the misfortune it brings and all.
Sorry, bunnies of the world.