Vomit-inducing guns have been the military's wet dream for years, and they've sunk million dollars into efforts to create one. Sure, there's always the good, ol' fashioned shoot-'em-till-they-stop-moving route, but the military also wants several non-lethal options at their disposal. So far, the Vomit Gun has eluded them, but they've managed to dream up plenty of other weapons whose creation have also failed: The Brown note would have caused your bowels to spontaneously evacuate, and they were hoping to make a "Gay Bomb," which would make you believe your trenchmate was the sexiest thing since Megan Fox. Lastly, there's a "Halitosis Bomb," producing a smell which no amount of Certs could cure. All of these non-lethal weapon schematics have been rejected by the Pentagon, because, really, who wants to see Call of Duty: Smelly Poop Fantasy become a reality?
However, where the US Navy has failed, two clever engineers with $250 spare change in their pockets have managed to make a vomit gun. With just a few LED lights, a heatsink from a computer and a nine-volt battery, you can have your very own spew phaser, too. Instructions on how to make one of your very own are available here.
Other failed military projects can be found in the "Harassing, Annoying, and "Bad Guy" Identifying Chemicals" PDF, but I will include some of the highlights:
The Day Star, It Burns!: Chemicals which would cause troops to become very sensitive to sunlight. Side effects include: World of Warcraft, poopsocks and an affinity for Cheetos.
Moses: The Plague Redux: Attract swarms of "stinging and biting bugs, rodents, and larger animals" to the enemy position with a chemical that makes them aggressive and annoying.
If you're reading this thinking "Man, the military doesn't get to create anything cool," fear not. The Pentagon has developed a small, possibly handheld weapon that will cause a "burning sensation " when the laser beam is directed at skin. Apparently, the burning sensation is enough to be incredibly uncomfortable, but stops just short of causing an actual burn. I'm guessing it hurts somewhere between electrolysis and an acid facepeel. The male equivalent would probably be severe razorburn. There's also a "Less Lethal Launcher" in development, a name that invokes the idea of "dead, but not quite," which I'm pretty sure will lead to the inevitable creation of zombies. For more fun "non-lethal" projects in the works, check here.