There are plenty of ways to ruin someone’s day, but nothing rivals the savagery of taking an upper decker.

For the uninitiated, an upper decker means taking a dump in the tank of a toilet. This prank has been known to shock innocent victims and cause seriously crappy plumbing issues (more on that later).

Upper deckers have been referenced everywhere from Hollywood to frat houses. But you’ve probably never witnessed one in real life. 

Lucky for you, we’re about to cover everything you wanted to know about upper deckers including what happens if you take one, how to clean up, and some iconic upper decker references in pop culture.

What Is an Upper Decker?

“Upper decker” is a slang term for pooping straight into the toilet tank, rather than the toilet bowl. After the deed is done, the next person to flush is greeted by a flood of poopy water, creating a mess and horrific stench. 

Crude as taking an upper decker may be, it’s actually an impressive feat. You have to perch yourself over the tank (not easy if you’re a big dude), then target your turd so it plops into the flush valve.

The earliest reference to upper deckers dates back to a 2003 Urban Dictionary entry. However, we wouldn’t be surprised if pranksters started taking dumps in toilet tanks much earlier, once they found out the damage it does.

People usually do upper deckers as a sinister prank. For example, someone in the r/confessions subreddit claims to have taken more than 100 upper deckers in various jerk’s toilets including his boss, the RA at his college dorm, and a guy who made a move on his girlfriend.

“It's so satisfying knowing someone is going to find my giant clogger and be disgusted that someone didn't flush it so now they have to look at it and smell it,” he explains. “Then they'll flush it themselves only for the bowl to be filled with dirty shit water.”

An upper decker is also known as a “Top Shelf Number Two,” although that doesn’t roll off the tongue quite as easily.

What Happens When You Take an Upper Decker?

You’d normally expect clean water when you flush. But taking an upper decker taints the toilet water with feces. As a result, you end up flushing with wastewater.

The exact outcome of an upper decker depends on the consistency of your poop. For example, a large, sausage-like turd that sinks to the bottom of the tank might not make its way through the valve and into the toilet bowl. But if you have diarrhea or floating poop, it’s almost certain the feces will come out the other end.

Regardless, an upper-decker will stink up the bathroom because the poop is just sitting there. The longer it takes for someone to notice, the worse the smell gets.

How to Clean Up After an Upper Decker

If you’re the victim of an upper decker, you might want to call a plumber so you don’t cause further damage to your toilet. But if you dare to resolve the situation yourself, here’s what one generous YouTube commenter advises:

1. Remove as much of the solid turd from the tank as you can
2. Close the valve to cut the water supply to the tank
3. Hold the toilet handle down to flush all the nasty sh*t water
4. Scrub and rinse any remaining poop from inside of the tank 
5. Pour vinegar into the toilet tank, wait five minutes, then drain it
6. Refill the tank with water and flush a couple more times

You might be tempted to whip out your plunger at the first sight of poop, but that won’t do anything. Remember, the problem is in the tank of the toilet—not the drain.

Upper Deckers In Pop Culture

Upper deckers aren’t just fodder for immature high schoolers. They’ve been the subject of dialogue in hit TV shows and movies.

Way back in a 2006 episode of The Ultimate Fighter, Richie Hightower took an upper decker in his opponent’s toilet. The deed led to a violent skirmish. 

“Pranks are pranks, but when you bring doo-doo into the equation that’s straight hostility,” said one cast member.

In season 6, episode 5 of The Office, Michael Scott invites Meredith to demonstrate effective conversation techniques. 

"So Meredith, how was your weekend? What did you do?" 

“Well I caught my son taking a dump on the upper part of the toilet... he calls it an ‘upper decker.’”

And we can’t forget about the iconic scene in MacGruber when the man himself proudly announces that he was late because he took an upper decker in the master bathroom.

Make a Clean Getaway with DUDE Wipes

We wouldn’t wish an upper decker on our worst enemies (even you, Charmin). There are certain lines you just don’t cross. But if you’re tempted to inflict this trauma on your enemies, you better prepare for two consequences:

1. A revenge upper decker in your own toilet
2. A messy rear

Don’t expect toilet paper to get all the poop residue off your nether regions. Snag some DUDE Wipes so you can make a clean escape after doing them dirty.