Question: Mr. & Mrs. Mxyzptlk is an episode of the superhero TV series that originally aired on what network?

Context:
Automan
Automan is an American soft science fiction superhero television series produced by Glen A. Larson.
 It aired for 12 episodes (although 13 were made) on ABC between 1983 and 1984.
 It consciously emulates the stylistic trappings of the Walt Disney Pictures film, "Tron", in the context of a superhero TV series.
Mr. &amp; Mrs. Mxyzptlk
"Mr. & Mrs. Mxyzptlk" is the thirteenth episode of the second season from The CW television series "Supergirl", which aired on February 20, 2017.
Mirrorman
Mirrorman (ミラーマン , Mirāman ) is the title superhero of a tokusatsu science fiction/kaiju/superhero TV series, Mirrorman.
 Produced by Tsuburaya Productions, the series aired on Fuji TV from December 5, 1971 to November 26, 1972, with a total of 51 episodes.
 This was Tsuburaya Productions' first non-Ultra superhero (even though there were concepts that were similar to "Ultraman", which became Tsuburaya trademarks).
 Like "Ultra Seven", "Mirrorman" was more of a dark and brooding science fiction drama than most other shows of its ilk.
 But by Episode 26, major changes were forced upon the series by the network (making the action lighter and the hero more like Ultraman), it became a typical action-oriented superhero adventure of its era.
Seven Color Mask
Seven Color Mask (七色仮面 , Nanairo Kamen ) is the name and title character of a tokusatsu TV series, later called New Seven Color Mask (新七色仮面 , Shin Nanairo Kamen ) .
 It was created by Kōhan Kawauchi, who also created "Moonlight Mask".
 This B&W TV show was the first superhero TV series by Toei Company Ltd..
 It was broadcast on NET (now TV Asahi) from June 3, 1959 to June 30, 1960, with a total of 57 episodes divided into 7 segments.
 Aside from being Toei's first superhero show, this series was also the debut of actor Sonny Chiba, who was 19 at the time, who took over the title role from Susumu Namijima after Episode 32.
Warrior of Love Rainbowman
Warrior of Love Rainbowman (愛の戦士レインボーマン , Ai no Senshi Reinbōman ) is a tokusatsu series created by Kōhan Kawauchi, this was the first superhero TV series produced by Toho Company Ltd., and was broadcast on NET (now TV Asahi) from October 6, 1972 to September 18, 1973, with a total of 52 episodes.
 Mitsuru Adachi wrote a manga series based on the show which was serialized in "TV Magazine Otomodachi" from 1972 to 1973.
Special Rescue Exceedraft
Special Rescue Exceedraft (特捜エクシードラフト , Tokusō Ekushīdorafuto ) is the last part of the Rescue Heroes Trilogy in Toei Company's Metal Hero Series of superhero TV series.
 It was aired in Japan from February 2, 1992 to January 24, 1993.
 The series was initially conceived as taking place in a new continuity, leading to weaker ties to Solbrain and Winspector.
Chouseishin Gransazer
Chouseishin Gransazer (Japanese: 超星神グランセイザー , Hepburn: Chōseishin Guranseizā ) , translated into English as "Ultra Star Gods and the GranSazers" or "Super Star Gods and the GranSazers" or also known as only "GranSazers", is a tokusatsu superhero TV series, produced by Toho Company Ltd., and Konami.
 The series aired on TV Tokyo from October 4, 2003 to September 25, 2004, with a total of 51 half-hour episodes.
 This series is the first of Toho's "Seishin (Star God)".
Supergirl (TV series)
Supergirl is an American superhero action-adventure television series developed by Ali Adler, Greg Berlanti and Andrew Kreisberg (the latter two having previously created "Arrow" and "The Flash") that originally aired on CBS and premiered on October 26, 2015.
 It is based on the DC Comics character Supergirl, created by Otto Binder and Al Plastino, and stars Melissa Benoist in the title role.
 Supergirl is a costumed superheroine who is Superman's cousin and one of the last surviving Kryptonians.
Android Kikaider
Android Kikaider (人造人間キカイダー , Jinzō Ningen Kikaidā ) , also known as Kikaida, is a tokusatsu superhero TV series and the first to feature the superhero Kikaider.
 Created by Japanese manga artist Shotaro Ishinomori, the show was produced by Toei Company Ltd., and was broadcast on NET (now TV Asahi) from July 8, 1972, to May 5, 1973, with a total of 43 episodes.
Jushin Liger (anime)
Jushin Liger (獣神ライガー , Jūshin Raigā , lit.
 "Beast God Liger", also sometimes romanized as "Juushin Liger", "Bio Armor Ryger", "Jushin Riger", "Jushin Ryger" and some other variations) is an anime superhero TV series created by Go Nagai.
 Produced by Sunrise Inc. with cooperation of Dynamic Planning (Nagai's own company), the series was originally broadcast on Nagoya Broadcasting Network (NBN)/TV Asahi from  11, 1989 (1989--) to  27, 1990 (1990--) with a total of 43 episodes.

Answer: CBS