You can't raise hell if you can't stand up — that's the idea behind a slimy substance designed by researchers at the Southwest Research Institute in San Antonio. The institute has developed a super-slimy goo that can be sprayed on rioters, much like the ectoplasm in Ghostbusters, I assume, and would make it impossible for them to keep their footing. The slime is so slick that not only would everyone fall down, but vehicles would be unable to get any traction as well. Police officers would spray rioters from a hose attached to a backpack with 3 cylinders: one with compressed air, one with water, and one with a very fine polyacrylamide powder that, when combined with the water, turns into the slick substance. And what happens after that? I suppose the that once the unruly mob is sufficiently sprayed and everyone is slipping and falling, the rioters will realize what a silly situation they're in and, with a sheepish look, realize that there really isn't anything to be mad about after all.
Riot Slimer, via New Scientist