Dullahan

The Dullahan is believed to be a manifestation of the Celtic god Crom Dubh, a dark harvest deity to whom human sacrifices were once made. When Christianity suppressed this cult, Crom Dubh's spirit became the Dullahan — a death portent that could not be locked out and could not be outrun. He rides a black horse, sometimes driving a coach made of human bones (the Coiste Bodhar), and stops where someone is about to die, calling out their name.

A headless horseman who carries his own rotting, luminous head under one arm. The head's face is described as having a hideous wide grin and eyes like small candles. His horse is black and has flames for eyes. His whip is made from a human spine.

No lock, gate, or door can remain closed when a Dullahan approaches. He cannot be stopped from reaching his destination. If he calls your name, you die. The only thing that repels him is gold — even a single gold pin thrown in his path causes him to vanish.