Seems like it was made by a cartoon cat

You have no idea what time it is when shot rings out from the far corner of your old one-room shack, but you know it's late. Adrenaline surging and ears ringing, you grab the old Colt revolver that sits on the stool beside your straw bed, thinking maybe those cattle rustlers the neighbors had been telling you about have finally got desperate enough to make a move on the property. Your bare feet hit the rough-hewn wood floor and you stumble as quickly as you can to the window, its little glass panes wavy and revealing nothing more than inky blackness. You're sure you heard the shot, but there's no signs of life outside save for the crickets that have resumed their song after only a few seconds intermission. You swear you can even smell the gunpowder smoke, but maybe it's your mind playing tricks on you, forcing alertness in the deep, lonely night. The adrenaline begins to wear, your limbs starting to ache as they long to go back to their fully interrupted sleep. You take a step to the left to turn from the window and you hear a sickening squelch and feel something squish between your toes that freezes you in your tracks. In the dim light given off by the fire smoldering in the cast-iron stove in the corner, you can tell that whatever it is is an ugly shade of red.

After a minute of silent contemplation, your brain puts it all together and your face quietly contorts into the most violent grimace it can muster. The goddamn trap that bastard salesman outside the general store had sold you down the river on the day before. The one that'd use your spare pistol. Well, he was right, it had worked. Now that rat that had eaten a hole in the corner of your bag of sugar decorates a small section of the wall, the floor, and the bottom of your foot and there's a warm black crater in the floorboard where it had made its last stand. Hobbling, you traipse outside to wipe your foot in the grass. Right there, you know what you must do. No matter what else, you're sure that bastard salesman won't be selling any more of those goddamn traps.

The patent

Imagine setting these up and then the cops getting called whenever they get set off. Its so stupid.

Yeah, but did it work?

I could see hikcok45 doing this

Fool-proof! What could go wrong!?

Shawn Woods on YouTube made a replica of this if you are interested seeing it in action.