A green mound, near the village of Pennygown (Peigh'nn-a-ghobhann), in the Parish of Salen, Mull, was at one time occupied by a benevolent company of Fairies. People had only to leave at night on the hillock the materials for any work they wanted done, as wool to be spun, thread for weaving, etc., telling what was wanted, and before morning the work was finished. One night a wag left the wood of a fishing-net buoy, a short thick piece of wood, with a request to have it made into a ship's mast. The Fairies were heard toiling all night, and singing, "Short life and ill-luck attend the man who asked us to make a long ship's big mast from the wood of a fishing-net buoy." In the morning the work was not done, and these Fairies never after did anything for any one.
From 'Superstitions of the Highlands and Islands of Scotland' by J G Campbell (1900).