Pranks are fun (sometimes). Exploding bottles of ketchup are fun (all the time). Cleaning up your kitchen because your exploding ketchup bottle prank was way more powerful than expected is never fun (NEVER). This guy planned to prank his girlfriend by making some fries and then giving her a ketchup bottle that would explode when she opened it. I'm guessing what he didn't expect was for his kitchen to end up looking like a volcano just unleashed its money shot all over his ceiling.
If you plan on pulling this prank, learn from this man's experience and do it outside. Unless you enjoy the challenge of figuring out how to get ketchup stains off your ceiling.