The Irish Dullahan is a type of unseelie faerie. It is headless, usually seen riding a headless black horse and carrying his head under one arm. The head's eyes are massive and constantly dart about like flies, while the mouth is constantly in a hideous grin that touches both sides of the head. The flesh of the head is said to have the color and consistency of moldy cheese. The dullahan's whip is actually a human corpse's spine, and the wagons they sometimes use are made of similarly funereal objects. When the dullahan stops riding, it is where a person is due to die. The dullahan calls out their name, at which point they immediately perish.

What characteristics of this being makes it to be considered a fairy?

1) supernatural creature
2) aspect of nature (death)
3) incorporation into folklore
4) insidious nature places dullahan into the unseelies, therefore "evil" faerie.