Killing zombies on campus just isn't as much fun as it used to be. Students at Bowling Green State University once carried Nerf guns for a week each semester, shooting the zombies before the creatures could tag them. Participants were seen by most bystanders as nerdy but harmless kids who liked role-playing. These days, bright plastic Nerf guns bring panicked phone calls to campus officials. Last fall the game freaked out several students and parents, who feared that the Nerf shooters might be on real rampages. Administrators called in the game's organizers and asked whether they could replace the fake guns with something that looked less like a weapon. The compromise: Players now throw marshmallows.