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A famous Welsh witch, who used to sleep under stone at Llanberis, in North Wales, was called Canrig Bwt, and her favourite dish at dinner- was children's brains. A certain criminal who had received a death-sentence was given the alternative of attacking this frightful creature, his life to be spared should he succeed in destroying her. Arming himself with a sharp sword, the doomed man got upon the stone and called on Canrig to come out. "Wait till I have finished eating the brains in this sweet little skull", was her horrible answer. However, forth she came presently, when the valiant man cut off her head at a blow. To this day they scare children thereabout with the name of Canrig Bwt.
[British Goblins (1881) by Wirt Sykes]