The outstanding upright stone at Stonehenge is so called. Geoffrey of Monmouth says the devil bought the stones of an old woman in Ireland, wrapped them up in a wyth, and brought them to Salisbury plain. Just before he got to Mount Ambre the wyth broke, and one of the stones fell into the Avon, the rest were carried to the plain. After the fiend had fixed them in the ground, he cried out, “No man will ever find out how these stones came here.” A friar replied, “That's more than thee canst tell,” whereupon the foul fiend threw one of the stones at him and struck him on the heel. The stone stuck in the ground, and remains so to the present hour.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894