This Ain't Your Mommy's Wonderland Anymore, Alice!

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. In another version, he is the headless driver of a black carriage. A similar figure, the gan ceann ("without a head"), can be frightened away by wearing a gold object or casting one in his path.

- Wikipedia