10 of the most unforgettable moments in the history of The Ultimate Fighter

#5: The Upper Decker (Season 6)

Season 6's Jon Koppenhaver took part in an outrageous moment involving a toilet

Following Joey Scarola's exit in the third episode, 2007's Season 6 settled down into a relatively low-key series by TUF standards. That was until an outrageous - and downright hilarious - incident in the 11th episode. The moment happened when members of Team Serra were inside the house, while Team Hughes were still training.

Three eliminated fighters - Richie Hightower, Jon 'War Machine' Koppenhaver, and Troy Mandaloniz decided to play a prank on their opponents - namely by defecating into the tank of their toilet, causing feces to flood into the pan upon flushing, a trick otherwise known as an 'upper decker'.

When Team Hughes returned to the house, star fighter Mac Danzig was instantly annoyed by the drunken laughing of the trio, but when the prank was discovered, he stayed relatively calm. Jared Rollins, on the other hand, lost his head entirely, smashed the top of the toilet tank and angrily confronted Koppenhaver, who then tackled him onto a bed.

Just as it seemed like things would spiral entirely out of control, cooler heads prevailed. Koppenhaver apologized, and joined Mandaloniz in cleaning the toilet - a disgusting job to say the least. While the incident was puerile, it was still outrageous to watch - and became one of the highlights of the season.