Exploding Key

“One of the most odd objects we’ve ever seen these items are sometimes confused with spy gadgetry, but the truth is stranger. Jailers’ keys were apparently filled with gun powder to create a primitive gun that could be detonated if there was any trouble when opening a cell door. We found several original versions that back up this claim, dating from the 17th century and of various complexity.” ~Oobject

Via Oobject.