This reminds me of a college professor grading 5 or 4 (cant remember for sure) of his students with F's (here we grade with numbers but to make it more appealing i said F :P). The respective students wanted revenge and to teach the teacher a lesson, so they were'd some mask and waited for him in park on his way home to beat the crap out of him. When they put there plan in to motion the next thing they now there all in the hospital beds with lots of broken bones. Eventually the teacher comes visiting them and say's: "If i knew you where actually my pupils i would have gone easy on you sorry guys", turns out the professor had a black belt with 5 dans at karate.