Question: Which American animated television series created by Trey Parker and Matt Stone features a character called Butters who thinks up schemes to take over the world in its 86th episode?

full_context: Document 1: South Park (season 10): The tenth season of "South Park", an American animated television series created by Trey Parker and Matt Stone, began airing on March 22, 2006. The tenth season concluded after 14 episodes on November 15, 2006. This is the first season in which Kenny does not die and the last season featuring Isaac Hayes (the voice of Chef) as Hayes quit the show following the backlash behind season nine's "Trapped in the Closet" episode. This season also had a minor controversy when the Halloween episode "Hell on Earth 2006" depicted "The Crocodile Hunter's" Steve Irwin with a stingray lodged in his chest getting thrown out of Satan's Halloween party for not being in costume. Episode 2 in this season is the last one with the Braniff Airlines logo. All the episodes in this season were written and directed by Trey Parker.
Document 2: South Park (season 7): Season seven of "South Park", an American animated television series created by Trey Parker and Matt Stone, began airing on March 19, 2003. The seventh season concluded after 15 episodes on December 17, 2003, and was written and directed by Trey Parker.
Document 3: The Biggest Douche in the Universe: "The Biggest Douche in the Universe" is the 15th episode of the sixth season and the 94th overall episode of the Comedy Central animated series "South Park". It was first broadcast on November 27, 2002 and was the last in a mini-arc depicting Cartman being occasionally possessed by Kenny. The episode is centered on Liane Cartman and Chef attempting to exorcise Kenny's soul while Stan deals with trying to debunk self-proclaimed psychic John Edward, whom the entire crew of South Park Studios agreed to be "the biggest douche in the universe." The episode is rated TV-MA in the United States, except on syndicated broadcasts, where the episode is rated TV-14, instead.
Document 4: South Park (season 4): Season four of "South Park", an American animated television series created by Trey Parker and Matt Stone, began airing on April 5, 2000. The fourth season concluded after 17 episodes on December 20, 2000.
Document 5: Reverse Cowgirl (South Park): "Reverse Cowgirl" is the first episode of the sixteenth season of the American animated sitcom "South Park", and the 224th episode of the series overall. It premiered on Comedy Central in the United States on March 14, 2012. In the episode, a nationwide catastrophe occurs after Clyde's mother is killed because Clyde forgot to put the toilet seat down and she did not bother to look before sitting.
Document 6: The Simpsons (season 6): "The Simpsons"' sixth season originally aired on the Fox network between September 4, 1994, and May 21, 1995, and consists of 25 episodes. "The Simpsons" is an animated series about a working class family, which consists of Homer, Marge, Bart, Lisa, and Maggie. The show is set in the fictional city of Springfield, and lampoons American culture, society, television and many aspects of the human condition.
Document 7: Simpsons Already Did It: "Simpsons Already Did It" is the seventh episode of the sixth season of the American animated television series "South Park", and the 86th episode of the series overall. It originally aired on Comedy Central in the United States on June 26, 2002. In the episode, which continues on from the events of the previous episode "Professor Chaos", Butters thinks up a series of schemes to take over the world, but realizes that each one has already been performed on "The Simpsons". Meanwhile, Ms. Choksondik dies and Cartman, Kyle and Stan think that they are responsible.
Document 8: Simpsorama: "Simpsorama" is the sixth episode of the twenty-sixth season of the animated television series "The Simpsons", and the 558th episode of the series overall. It originally aired on the Fox network in the United States on November 9, 2014. "Simpsorama" is a crossover with "Futurama", another animated series created by "The Simpsons" creator Matt Groening, that had previously aired on Fox and later Comedy Central before concluding in September 2013.
Document 9: South Park (season 2): Season two of "South Park", an American animated television series created by Trey Parker and Matt Stone, began airing on April 1, 1998. The second season concluded after 18 episodes on January 20, 1999; it remains the longest season of "South Park" to date. While most of the episodes were directed by series creator Trey Parker, Season 2 includes two episodes directed by Eric Stough.
Document 10: South Park (season 1): The first season of the animated television series "South Park" ran for 13 episodes from August 13, 1997 to February 25, 1998 on the American network Comedy Central. The creators Trey Parker and Matt Stone wrote most of the season's episodes; Dan Sterling, Philip Stark and David Goodman were credited with writing five episodes. The narrative revolves around four children—Stan Marsh, Kyle Broflovski, Eric Cartman and Kenny McCormick—and their unusual experiences in the titular mountain town.
Document 11: South Park (season 8): Season eight of "South Park", an American animated television series created by Trey Parker and Matt Stone, began airing on March 17, 2004. The eighth season concluded after 14 episodes on December 15, 2004, and was written and directed by Trey Parker. The season deals with various topics that were relevant at the time of release. The episodes portray a spectrum of topics, from effect of large scale retails corporations to immigration.
Document 12: Who Shot Mr. Burns?: "Who Shot Mr. Burns?" is a two-part episode of the American animated television series "The Simpsons". Part One is the twenty-fifth and final episode of the sixth season and originally aired on the Fox network in the United States on May 21, 1995, while Part Two is the season premiere of the seventh season and aired on September 17, 1995. Springfield Elementary School strikes oil, but Mr. Burns steals it and at the same time brings misery to many of Springfield's citizens. Part One has a cliffhanger ending where Mr. Burns is shot by an unidentified assailant. In Part Two, Springfield's police try to find the culprit, with their main suspects being Waylon Smithers and Homer Simpson.
Document 13: South Park (season 9): Season nine of "South Park", an American animated television series created by Trey Parker and Matt Stone, began airing on March 9, 2005. The ninth season concluded after 14 episodes on December 7, 2005. All of the episodes in the ninth season were written and directed by Trey Parker.
Document 14: Death (South Park): "Death" is the sixth episode in the first season of the American animated television series "South Park". It originally aired on Comedy Central in the United States on September 17, 1997. In the episode, Grandpa Marvin tries to convince Stan to kill him, while the parents of South Park protest the foul-mouthed cartoon "Terrance and Phillip". Death himself arrives to kill Kenny, and presents a warning to Grandpa Marvin against forcing others to help him commit suicide.
Document 15: South Park (season 6): Season six of "South Park", an American animated television series created by Trey Parker and Matt Stone, began airing on March 6, 2002. The sixth season concluded after 17 episodes on December 11, 2002. This season is notable for being the only one without Kenny as a main character, as he was written off in the previous season. Kenny, however, plays a part in some episodes without appearing and returns at the conclusion of the final episode.
ground_truth: South Park