You spend at least 40 hours a week with these people, so sooner or later you're going to get sick of small talk and want to have a little bit of fun at their expense. So when you hear the news that Jim down in sales is taking a holiday, you know just what you have to do: an epic office prank. He won't know what hit him. Of course, when it's time for you to go on a vacation of your own, you better watch your back!
Here are 18 diabolical office pranks that will make you scared to take a sick day: