The U.S. military has a lot of great options when it wants to kill the enemy. Some of the world's best planes, artillery, and helicopters work with ground pounders to dominate lethal operations.
But when it comes to dealing with crowds, the military wants more options. One of its most promising candidates is the Active Denial Technology system, which focuses a beam of energy to heat the target's skin 1/64 of an inch deep. It creates a sensation of sudden heat and pain, convincing the target to run.