There is something about the symbolism around the head and the skull that intrigues me, to me the image of a Headless horse is just as Provocative and Captivating as a Headless Man. 

excerpts from Wikipedia 


The Irish dullahan (also Gan Ceann, meaning "without a head" in Irish) 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.
There is no way to bar the road against a dullahan—all locks and gates open on their own when it approaches. 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. Nonetheless, they are frightened of gold, and even a single gold pin can drive a dullahan away.

In Celtic folklore

The Irish dullahan or dulachán ("dark man") is a headless fairy, usually riding a black horse and carrying his head under one arm (or holding it high to see at great distance). He wields a whip made from a human corpse's spine. When the dullahan stops riding, a death occurs. The dullahan calls out a name, at which point the named person immediately perishes.^[2] In another version, he is the headless driver of a black carriage.^[3] A similar figure, the gan ceann ("without a head") can be frightened away by wearing a gold object or casting one in his path.^[4]
The most prominent Scottish tale of the headless horseman concerns a man named Ewen decapitated in a clan battle at Glen Cainnir on the Isle of Mull. The battle denied him any chance to be a chieftain, and both he and his horse are headless in accounts of his haunting of the area.^[5]
Sir Gawain and the Green Knight is a Middle English poem which utilises a decapitation myth.

 In German folklore

The German Legends of the Brothers Grimm (Deutsche Sagen) recount two German folk tales of a headless horseman.
One is set near Dresden in eastern Germany. In this tale, a woman from Dresden goes out early one Sunday morning to gather acorns in a forest. At a place called "Lost Waters", she hears a hunting horn. When she hears it again, she turns around she sees a headless man in a long grey coat sitting on a grey horse.
In another German tale, set in Brunswick, a headless horseman called "the wild huntsman" blows a horn which warns hunters not to ride the next day, because they will meet with an accident.
In some German versions of the headless horseman, he seeks out the perpetrators of capital crimes. In others, he has a pack of black hounds with tongues of fire.