Iron maiden

An iron maiden is a medieval torture device. The following short quote from Brewer's Dictionary of Phrase and Fable describes the 'Iron Maiden of Nuremberg' which was an example of such a device used in Germany in the 16th Century:

An instrument of torture for heretics, traitors, parricides, etc. It was a box big enough to admit a man, with folding-doors, the whole studded with sharp iron spikes. When the doors were pressed-to these spikes were forced into the body of the victim, who was left there to die in horrible torture. (German, Eiserne Jungfrau)

The name has also been adopted by Heavy Metal group Iron Maiden.