"I Should Have Never Gone Ziplining" is the sixth episode of Season Sixteen, and the 229th overall episode of South Park. It aired on April 18, 2012.
The boys are excited to spend a day ziplining in the Colorado Mountains. But high in the Rockies, far from their families, their trip takes a bad turn. Chances of survival are slim. All they can do is wait to be rescued. But will help come too late?
The episode opens dramatically, with the boys screaming for help while a male voice narrates the boys' misfortunes. Shortly after, the voice continues to narrate, revealing that it is the last day of spring break.
The boys argue over what to do, however, one of the boys recommends ziplining, ending their argument as they unanimously agree with the recommendation. After Stan's uncle, Jimbo drops them off, an employee prepares them to go ziplining; he later reveals that there are other people ziplining as well. After watching a safety video, they, much to their chagrin, realize they have to take a shuttle to the ziplining spot.
After they arrive at the spot, the boys go ziplining, learning that it is, in fact, very boring. This upsets them severely, as they realize they are wasting their last day of spring break. After learning that there are sixteen more ziplining spots to go, they scream for help. Cartman and Kyle later start arguing over who came up with the idea of ziplining in the first place, however, Stan breaks up this argument, saying they can make it somehow. They later make up an excuse to leave, telling the employees that Kenny is bleeding severely from his cold sore (herpes). The employees say that they cannot do anything from zipline down, however, one of the employees recommends going to a horse ranch near the ziplining site, saying that they could ride back.
After arriving at the horse ranch, they realize that it is a tour group as well. After Kyle starts to give up, Stan notices that there is boating dock nearby, saying they should get on, as it will be fun. The screen then flashes to a warning stating that the program contains reenactments; from here on in the episode, the boys misfortunes are reenacted by live-action actors. They realize they made the same mistake, as the boat is only allowed to go five miles per hour, making the trip boring once again.
Kyle and Cartman resume their earlier argument over who recommended they go ziplining. However, Cartman begins to have diarrhea, attracting beavers. Kenny is later revealed to have died of boredom, once again inciting Kyle and Cartman to argue. Stan, fed up with the drama, reveals he was the one who recommended they go ziplining. Cartman and Kyle ask why, resulting in Stan revealing that, if he signed up three friends, the ziplining company would give him a free iPod Nano. After briefly becoming angry with Stan, they all begin crying.
Shortly afterwards, Mr. Hankey comes to bring them back home, taking them aboard his "Magical Helicrapter", his "7-turdy-7" airplane, and his "Poo-Choo Express".
The voice, continuing it's narration, reveals that Kenny's corpse was left at his families' home, Cartman and Stan were treated for their (cold sores) herpes, and Kyle was put in the hospital for twenty-seven days, as he had to have fecal matter removed from his nose. After Stan was treated for his condition, he successfully raised awareness about the dangers of ziplining through popular videos, resulting in him once againmasturbating in San Diego. Two weeks after he was treated, Cartman begins drinking Diet Double Dew again, namely because he believed that "diet soda doesn't give you diarrhea".