Is there anything that you can get easily that you can put in some food or something that if someone ate it they wouldn't know anything was in it and it would give them diareah or put them to sleep?
That might work I'l melt them into something else so there isn't an "exlax" on it and that will teach that fucker to eat everyone's food
some of my friends put some ex-lax into a teachers coffee once, yeah, he had to leave school for the day...