The Fachan (Fechan or Fachin or Peg Leg Jack) is a found in Scots-Irish Folklore. A Fachan’s appearance is so terrible it was known to cause heart attacks. It has one eye, one leg, one withered arm coming out of it’s chest and a mane of black feathers.
Nesnas Mhiccallain or Direach Ghlinn Eitich, (the Dwarf of Glen Etive, (Argyll)) was a Fachan that lost a race against Murachadh MacBrian, King of Ireland in John Francis Campbell’s Popular Tales of the West Highlands.
It has been suggested that the Fachan is an imperfect memory of Celtic Seers who when casting spells would stand on one leg, close one eye and extend one arm.