ifyouwatchitbackwards:

Have you ever thought about turning your house key into a gun? Probably not. But some people back in the 17th century did and they brought the idea to fruition. They created muzzle loading pistols that allowed jailers to have a drawn gun while they were unlocking cells. The keys were filled with gun powder to create a primitive gun that could be shot off if a prisoner tried to make a break for it when the cell door opened. These guns came in various complexities and forms.