Wind up chattering teeth. Or maybe get the wrapper from a blue diamond almond can and put it on those spring loaded snakes that pop out when you open it. Since its an office gift, maybe raid the office supply room and use sticky pads or a toner cartridge.
My family likes to put junk in a cool box. Like a shoe box full of leftover chicken bones. You have to know the person though...one persons gag is anothers insult.