I snagged this from Lord Gwydion at the What a Horrible Night to have a Curse... blog, renamed it and changed the text significantly.
Move: 120 (40) (or as mount)
Attacks: 1 Bone Whip
Damage: 1d8 Save vs Spells on a hit or become Blind
No. Appearing: 1 (1-4)
Save As: F6
Treasure Type: A (U)
The Dullahan, is a type of Unseelie fairie. It is headless, usually seen riding a black horse and carrying his or her 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 (e.g. candles in skulls to light the way, the spokes of the wheels made from thigh bones, the wagon's covering made from a worm-chewn pall). 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 (Finger of Death).
There is no way to bar the road against a Dullahan—all locks and gates open on their own when it approaches (Knock). Also, they do not appreciate being watched while on their errands, throwing a basin of blood on those who dare to do so (often a mark that they are among the next to die), or even lashing out the watchers' eyes with their whips (Cause Blindness). Nonetheless, they are frightened of gold, and even a single gold pin can drive a Dullahan away. but can also use the following spells: Knock, Cause Fear (at will), Cause Blindness (once per turn), Finger of Death (once per day). As Unseelie creatures, Dullahan are immune to sleep, charm and hold magic. They can be Turned as Vampires.