This prehistoric cromlech burial chamber is said to be an abode of the fairies - as a farmer that lived directly nearby happened to make one his wife. John Rhys relates a story about in his Celtic Folklore Welsh And Manx:
I walked across to Criccieth Station; but on my way I was directed to call at a farm house called Llwyn y Mafon Uchaf, where I was to see Mr. Edward Llewelyn, a bachelor then seventy-six years of age. He is a native of the neighbourhood, and has always lived in it; moreover, he has now been for some time blind. He had heard a good many fairy tales.
.. He told me of a man at Ystum Cegid, a farm not far off, having married a fairy wife on condition that he was not to touch her with any kind of iron on pain of her leaving him for ever. Then came the usual accident in catching a horse in order to go to a fair at Carnarvon, and the immediate disappearance of the wife. At this point Mr. Llewelyn's sister interposed to the effect that the wife did once return and address her husband in the rhyme, "Os bydd anwyd arfy mab", etc. Then Mrs. Llewelyn enumerated several people who are of this family, among others a girl, who is, according to him, exactly like the Fairies.