Some of the funniest pranks are some of the easiest pranks, like this toothpaste prank. It's very simple, and if you follow the instructions, you'll be able to booby trap your roommate's toothpaste for a very fun time. It can be very gross if you deem necessary.
All you have to do is squeeze all of the toothpaste out of your victim's tube and fill it back up with whatever you desire. In the video, apple juice is used. After you fill it up, make sure you sap a little toothpaste on the tip of the tube, to make it look natural. This is a great April Fool's prank.