Researchers at the Southwest Research Institute in San Antonio, Texas are apparently huge fans of The Ghostbusters. A recent patent filed by them shows a tank of goo carried backpack-like by riot police.
A hose extends from the tank to a nozzle, which when shot, combines a jet of water with a jet of dry powder into a single powerful stream of splurge that causes everybody in the area to fall down. Even cars are not immune as they go sliding faster than a Japanese drifter.
Any invention that calls for less bean bags shot to our face is a good one in our book.
Riot slimer [NewScientist]