This one's true...
When I was a kid, we used be able to buy cookies after lunch in the school cafeteria. My favorite was Oreos. They were 2 cents apiece, and my Dad would give an extra dime in my lunch money to buy 5 of them. I was a bit of a runt back then, and there was one particular guy who picked on me all the time. One day he decided he would snag an Oreo off the top of my little stack as he walked by. Soon it became a daily habit. I wasn't too bad with my fists, but this guy was way bigger, so I just kinda endured it.
One day I told my Dad what was happening, and how big the guy was, and he came up with this great scheme to doctor up an Oreo with red pepper flakes. He took apart an Oreo from the pack we had at home, hollowed out the center of the cream filling, put the pepper flakes in the hole and put the top back on.
The next day, after I bought my Oreos, I slipped the loaded cookie on top of the stack and waited. I kept looking out the corner of my eye, and sure enough, I saw him making a beeline for my table. Just as he was ready to grab it, I looked him right in the eye, and he hesitated and then walked on without taking it. I was really disappointed, even though I was pretty sure I was going to get an ass kicking over it. I really wanted to see his face when that pepper hit his tongue. It would have been worth the beating.
After that, he never tried to snag another cookie again. And about a year later we started to hang out and we got to be friends.