Zombies could be involved. Seriously.
A food fight in which there was this fat kid that was eating all of it anyway. Some nerdy kid knew that it was gonna happen and he wanted to make sure the whole school paid for it--so he injected his peanut butter and jelly sandwich with some zombie fluid, and the fat kid ate it and then started eating the kids and they couldn't get out of the cafeteria because the doors were locked and all the administrators and adults in the school had been eaten, and there'd be nowhere to hide because it'd be a small cafeteria.
