Israel had a machine they brought out into riots that would make a sound that would cause people to lose control of their bowels, and to vomit- supposedly- roll them out- make the streets look like LA
His brother was an LAPD academy cadet in class when a sweet young thing brought in a big ominous-looking black box, plugged it in, flipped a switch and smiled as all the cadets (all male then) grabbed their crotches and lurched for the door. Somehow the box emitted a very low frequency sound which relaxed the adult male bladder. But it only worked indoors so it wasn't practical for crowd control then.
Israel seems to have solved that problem.