What is "dullahan"

The Irish dullahan (also Gan Ceann, meaning "without a head" in Irish) is a type of unseelie fairy.

Dullahan (February 8, 2009 – October 20, 2013) was an American Thoroughbred racehorse. As a two-year-old he recorded his first win in the Grade I Breeders' Futurity Stakes. In early 2012 he won the Blue Grass Stakes, finished third in the Kentucky Derby and was the beaten favorite for the Belmont Stakes. Later in the season he defeated older horses in the Pacific Classic. He died of a ruptured colon on October 20, 2013 at Winstar Farm in Versailles, Kentucky.