What is "brazen bull"

n. An ancient torture device, supposed to have been devised by (w: Perillos of Athens), consisting of a hollow bull fashioned from brass in which victims were imprisoned and burned to death.

The brazen bull, bronze bull, or Sicilian bull, was a torture and execution device designed in ancient Greece. According to Diodorus Siculus, recounting the story in Bibliotheca historica, Perillos of Athens invented and proposed it to Phalaris, the tyrant of Akragas, Sicily, as a new means of executing criminals. The bull was made entirely of bronze, hollow, with a door in one side. The bull was in the form and size of an actual bull and had an acoustic apparatus that converted screams into the sound of a bull. The condemned were locked in the device, and a fire was set under it, heating the metal until the person inside roasted to death.