Naturally, no good deed goes unpunished, and Professor Snape, looking freshly washed, came into the corridor just in time to see one of his students run away screaming. Looking around, his face lit up as he saw the son of his nemesis. "Potter! What are you doing? Put that wand away! It's bad enough that you show off in class, but, assaulting students in the halls? That will be 50 points from Gryffindor, and you will be joining me in detention every night this week. Perhaps cleaning cauldrons will break your habit of breaking the rules, probably not, but, at least you won't have the time to spend with your muggle-born girlfriend!" He ended with a look of disgust as he walked away.