“Sleep well sweet angel, let no fears of ghouls disturb thy rest, for above thy shrouded form lies a torpedo, ready to make minced meat of anyone who attempts to convey you to the pickling vat.” How’s that for an advertising slogan?
Welcome to the wonderful world of grave booby traps. In the beginning, they were simply a way to keep nocturn animals from digging up fresh meat. When there were no night watchmen, the person who oversaw the graveyard simply took a gun and modified it slightly. They added a spike, so they could drive it down into the ground like a lawn flamingo, and usually weighted it well, so the recoil wouldn’t spoil the aim. Then they added a tripwire to the trigger.
These guns did very well in the days when life was cheap– especially to the sort of people who could afford firearms for their dead bodies. Still, being dug up and pawed at was a valid concern. People were often buried with valuables. Even if they weren’t, dead bodies were always of interest to both doctors and artists. Even today, there is a black market for human organs, the bulk of which are supplied by shady undertakers.
Eventually grave guns fell out of both fashion and legality. In the early 1800s, too many people met their end by catching a bullet in a dark cemetery. At the same time, a wider interest in medical sciences, and a recognition of the importance of anatomy, drove up the demand for bodies. Grave cages and grave torpedoes hit the market. Grave cages were just meant as one more hindrance for grave robbers.
And then there were torpedoes. Attached to the lid of a coffin by a metal plate, they were primed and set to blow up in the face of the first person to lift the lid. Naturally, they wouldn’t stay ready forever, but after a few months, any body lost its value. Today, more people are donating their bodies to science, but bodies are still in short supply. (Technically, grave guns and torpedoes are illegal now, but—what are they gonna do to you? Execute you?)
[Source: Grave Guns and Grave Torpedoes]