The brazen bull of Phalaris. Perillos, a brass-founder of Athens, proposed to Phalaris, Tyrant of Agrigentum, to invent for him a new species of punishment; accordingly, he cast a brazen bull, with a door in the side. The victim was shut up in the bull and roasted to death, but the throat of the engine was so contrived that the groans of the sufferer resembled the bellowings of a mad bull. Phalaris commended the invention, and ordered its merits to be tested by Perillos himself.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894