The classic spring-loaded moustrap design, first patented in 1884 by one William C. Hooker, is basically the one we still use today. But two years earlier, one Jason Alexander Williams of Fredonia, Texas had a different kind of spring-loaded design in mind… one that heavily relied on the use of a .50 caliber bullet.
In his patent application, Williams states that his aim was “to provide a means by which animals which burrow in the ground can be destroyed, and which trap will give an alarm each time that it goes off, so that it can be reset”. A gunshot would certainly be loud enough to alert any person nearby that the trap has gone off, though the method of delivery would probably leave nothing more of the rodent but a smear on the ground.
But of course, even though this invention was patented as an “animal trap”, Williams saw further potential in his idea. “This invention may also be used in connection with a door or window, so as to kill any person or thing opening the door or window to which it is attached”, the patent application continues. While Williams states he was aware that similar methods of “burglar alarms” in which a gun was attached to a door or window have been used in the past, “in no case have the parts been arranged and combined as here shown and described”. So if anyone intended so secure his door with a revolver, he would infringe on Williams’ patent.
Williams filed his application for his new and improved mousetrap on August 21st, 1882 at the United States patent office. The patent was granted on December 26th of the same year.