Generally, mankind does not outlaw weapons. Anything a military can think of is in the arsenals of the world. But there are a few exceptions and one of them is for a weapon so hideous that virtually every country has banned, not only its use, but the mere possession of it. The weapon is sarin. It's nerve gas. And in 2013, it was unleashed on Syrian civilians in what the U.N.'s secretary general calls, "a crime against humanity.