The Pooka
A shape-shifting spirit, found in folklore across Ireland, Scotland, the Isle of Man, and Wales. Most often it appears as a black horse with luminous yellow eyes that snatches up travellers and runs them across the country until dawn. Sometimes a hare, sometimes a goat, sometimes an eagle, sometimes a man with the head of an animal. The Pooka is hostile to drunks and lazy farmers but generous to those who leave it a share of the harvest. It is most active around Samhain. After 1st November, you do not pick blackberries. The Pooka has been at them.
Folklore Commission of Ireland (Coimisiún Béaloideasa Éireann) archive; Ó hÓgáin, The Lore of Ireland (2006)