Quoting from Wikipedia here:
A petard was a small bomb used to blow up gates and walls when breaching fortifications. The term has a French origin and dates back to the sixteenth century. In a typical implementation, it was commonly either a conical or rectangular metal object containing 5 or 6 pounds of gunpowder, activated with a slow match used as a fuse. Petard remains a French word meaning a firecracker today (in French slang, it means a handgun, or a joint). The word remains in modern usage in the phrase hoist with one's own petard, which means "to be harmed by one's own plan to harm someone else" or "to fall into one's own trap", literally implying that one could be lifted up (hoist, or blown upward) by one's own bomb.
So when you go to the store and buy one of those wash-off glass marking pens that are supposed to be used to write slogans such as "Marge and Nick 4ever" or "Good Luck Seniors" or "For Sale Runs Good" on the window of the car, but instead you write "THIS IS AMERICA AND OUR ONLY LANAGUAGE IS ENGLISH"...consider yourself hoist.
Sic Semper Stupid.