This is a list of "Treehouse of Horror" episodes produced by the animated television series "The Simpsons".
 "Treehouse of Horror" episodes have aired annually since the second season (1990) and each episode has three separate segments.
 These segments usually involve the family in some horror, science fiction, or supernatural setting and always take place outside the normal continuity of the show and are therefore considered to be non-canon. "
Treehouse of Horror" episode aired on October 25, 1990 and was inspired by EC Comics Horror tales.
 Before "Treehouse of Horror XI", which aired in 2000, every episode has aired in the week preceding or on October 31; "Treehouse of Horror II" and "Treehouse of Horror X" are the only episodes to air on Halloween.
 Between 2000 and 2011, due to Fox's contract with Major League Baseball's World Series, several episodes have originally aired in November; as of 2011 every "Treehouse of Horror" episode has aired during the month of October.
 From "Treehouse of Horror" to "Treehouse of Horror XIII", all three segments were written by different writers and in some cases there was a fourth writer that wrote the opening and wraparound segments.
 For "Treehouse of Horror", there were even three different directors for the episode.
 Starting with season fifteen's "Treehouse of Horror XIV", only one writer was credited as having written a "Treehouse of Horror" episode, and the trend has continued since.
"The Corbomite Maneuver" is a episode of the American science fiction television series, "", first aired November 10, 1966, and repeated May 11, 1967.
 It is episode No. 10, production No. 3, the first regular episode of "Star Trek" produced after the two pilots, although it was aired later in the season.
"Professor Chaos" is the sixth episode of the sixth season of the Comedy Central series "South Park" and the 85th episode of the series overall.
 It originally aired on April 10, 2002.
 The boys hold a contest to try to find a replacement for Butters, who becomes a supervillain after being fired from the group as the replacement Kenny.
 The show also parodies "The Bachelor."
"Moonshine River" is the first episode of "The Simpsons"' twenty-fourth season.
 It originally aired on the Fox network in the United States on September 30, 2012.
 In the UK and Ireland, the episode aired on Sky 1 on 24 March 2013 with 1,295,000 viewers, making it the second most watched program that week.
 The episode has ten guest stars, Ken Burns, Zooey Deschanel, Sarah Michelle Gellar, Anne Hathaway, Maurice LaMarche, Don Pardo, Natalie Portman, Kevin Michael Richardson, Al Roker and Sarah Silverman.
 Deschanel, Gellar, Hathaway, Portman and Silverman reprise their roles as Bart's previous love interests, Mary Spuckler (from "Apocalypse Cow"), Gina Vendetti (from "The Wandering Juvie"), Jenny (from "The Good, the Sad and the Drugly"), Darcy (from "Little Big Girl") and Nikki (from "Stealing First Base"), respectively.
 This is the second episode in which the Simpsons go to New York City, the first episode being "The City of New York vs. Homer Simpson".
 The title is a parody of the 1961 Academy Award-winning song, "Moon River".
Era mio Fratello (Translation: "He was my Brother") is a two episode television miniseries that aired in 2007 on Rai Uno.
 The first episode aired on 30 September 2007 in Italy and the second episode aired on 1 October that same year.
 It is the first Italian television series having 'ndrangheta as main theme.
 Filming took place in Calabria, in the cities of Reggio Calabria, Palmi, Catona, Melito and Pentedattilo.
 The "La Repubblica" television critic apprecciated the miniseries, commenting that it has "the same rhythm and language of the most modern crime series".
Lady for a Day was an Australian television game show which aired from 1960 to 1962 on Melbourne station HSV-7.
 Hosted by American Larry K. Nixon, the first episode aired 8 August 1960 while the final episode aired 8 August 1962.
 It was based on controversial US series "Queen for a Day".
 Each episode was 60 minutes, and the series aired 5 days a week.
 The archival status is unknown, although clips from at least one episode have appeared in television retrospectives.
Call for Help, also known as CFH, is a computer-themed television program that first aired exclusively on TechTV (formerly "ZDTV"), a cable and satellite television network focused on technology, and then aired on G4techTV Canada and the HOW TO Channel in Australia.
 The final taped episode aired on February 26, 2007, but because the episodes were taped out of order, a number of other episodes taped during the same shooting week aired through April 6, 2007.
 A spin-off called "The Lab with Leo Laporte" aired much of the same content as "Call for Help" and ran on the same networks.
 "The Lab" was canceled about one year later due to low viewer ratings and the final episode aired in August 2008.
"Man's Best Friend" is a controversial episode of Nickelodeon's "The Ren & Stimpy Show" that was produced for the 2nd season of the show, but it never aired in the original run of the series.
 It was aired later on Spike TV as the first episode of "Ren & Stimpy "Adult Party Cartoon"".
 In this episode, Ren and Stimpy are adopted by George Liquor, who wants to make them champions.
"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.
"The Princess Guide" is the fifteenth episode of the twenty-sixth season of the American animated sitcom "The Simpsons", and the 567th overall episode of the series.
 It originally aired on the Fox network in the United States on March 1, 2015.
 The episode was dedicated to the memory of Leonard Nimoy, who died two days before the episode aired.
 Nimoy guest-starred in two "Simpsons" episodes, "Marge vs. the Monorail" and "The Springfield Files".

Question: Which episode aired later, Simpsons Already Did It or Professor Chaos?
Answer: Simpsons Already Did It