Slang (Obsc.) - An extremely high pressure, loud type of fart which was supposedly banned under the terms of the Geneva convention, owing to the fact that it is so powerful, that it leaks out of your trouser leg and can destroy anything within a 5 mile radius of where you were standing when you dropped it.
Supposedly has the effect of a large green 8 mile high mushroom on the horizon, which is how you spot when someone left one behind.
Classed as a Category 1A Biological Weapon.
"Man, you wanna stop leaving those Geneva Shitcloud's behind, or you gonna get the ATF on your a*se!"