Sometimes I like to think about weird things...really weird things.
For instance I have often wondered how would the Civil War have been changed if you gave the South one M-16. Lets assume they also have a virtually unlimited amount of ammo for it. The only logistical issue they would have to deal with is transporting the ammo around from battle to battle. I'm pretty certain the war would easily be won by the south under this scenario. Basically all they would have to do is keep the gun from getting stolen and prevent it from getting hit by cannon fire. The former the gun itself could prevent. Feel free to disagree but the range, accuracy, rate of fire and reliability of the M-16 would be virtually unstoppable in that era.
You might be saying "That's not all that weird"
So with that situation fairly one sided in my mind I began to think, what if they had one M-16 yada yada yada BUT instead of the bullets killing and/or injuring they made the victim poop their pants.
I think this would affect the fighting abilities of the north quite a bit. But clearly not as much as if they were dead. For one they arent going to be able to move around as well, and for two its gonna start to smell real real bad when a whole row of infantry gets mowed down. You also have to throw the shock factor in there. Randomly messing your knickers while being shot at probably dazes you for a short while. So now to my ESPN like analysis of an overly hyped event that is never going to take place. SIDE NOTE: I find it hilarious that the two teams they said would beat almost every historic team they matched them up with ('08 Patriots and '05 USC) lost in the game they were yet to play that season. HA. Anyway, here is how I see it. The South would benefit greatly from this odd technology early on when some soldiers freeze up and are then killed while other retreat to empty their drawers. However, it is possible this would result in less casualties but I'm not really sure if men would retreat or just deal. I mean hygene wasnt exactly the most important thing back then. I do believe that todays athlete is just too great and between Randy Moss' freakish abilities and Tom Brady's dreamy eyes, wait thats not right. Oh yeah I think the North would sooner rather than later figure out what was happening and move to fighting in sometype of an assless chap. This would render the weapon virtually useless provided they seperate their lines a little bit more than usual.
So in Summary
Winner of Civil War - NORTH
Winner of Civil War if South had an M-16 - SOUTH
Winner of Civil War if South had an M-16 that made you poop your pants - PROBABLY NORTH STILL BUT IT WOULD HAVE BEEN A LOT CLOSER AND A LOT MESSIER
P.S. This isn't that wierd an idea, the military has actually done a lot of research on the "Brown note". The idea that a low enough pitch tone can cause people to lose total control of their bodily function thus making them not really want to shot guns or have guns shot at them. So that is the answer to your question "How in the world did he think of that?"