The dullahan is a type of Irish fae categorised in the unseelie court. Its head is permanently separated from its body, which it carries under its arm. It will always arrive riding a black horse and sometimes come accompanied with a wagon cobbled together out of skeletons. Either of these modes of transport will travel with speed so fast the sparks given off could set alight the roadside growth. Its rotted face is rumoured to have huge eyes and a very wide grin.

Like the Ankou its purpose is to claim the souls of whatever parish it visits. It will stop riding where a person is due to die and call out that name. It is impossible to bar the way of the dullahan as any obstacle will unlock and open in its path. Any onlookers are discouraged from watching its canter. It will throw a basin of blood on these people (sometimes fatal) or else lash out with its whip made of spinal cord. The only known way to repel the creature is the use of gold. The dullahan is fearful of the element and will run from the mere sight of it.

Suggested origins are not always agreed upon, but many think that it is the regressed spirit of the ancient Celtic God 'Crom Dubh'. The spirit demanded sacrifices of human souls and was denied this when its worship was abandoned. Its festival reputedly took place somewhere in late August to early September. There were prime sightings of the dullahan at this time.

This myth may have inspired the fictional legend of the Headless Horseman and bares resemblance to the Arthurian tale of the Green Knight.