Aillen Mac Midhna was a fairy musician of the Tuatha de Danann who came every year at Samhain Eve (All-Hallow Eve) out of Sidhe Finnachaid to Tara, the Royal Palace of the High King, playing so marvellously on his timpan (a kind of belled tambourine) that all who heard him were lulled asleep, and while they slept he blew three blasts of fire out of his nostrils and burnt up the Hall of Tara.

This happened every Samhain Eve for twenty-three years, until Finn of the Fianna Finn conquered Aillen and killed him (Silva Gadelica vol. II, pp. 142-4). He conquered him by himself inhaling the fumes of his magic spear, whose point was so venomous that no one who smelled it could sleep, however lulling the music.

SOURCE:

An Encyclopedia of Fairies: Hobgoblins, Brownies, Bogies, and Other Supernatural Creatures written by Katharine Mary Briggs – Copyright © 1976 by Katharine Briggs