Question: Which studio produced the movie which had a 21-minute Halloween television special based on it that premiered on Wednesday, October 16, 2013?

Context paragraphs:
Toy Story (franchise): Toy Story is a computer animated film series and Disney media franchise that began with the original 1995 film, "Toy Story", produced by Pixar Animation Studios and released by Walt Disney Pictures.  The franchise is based on the anthropomorphic concept that all toys, unknown to humans, are secretly alive, and the films focus on a diverse group of toys that feature a classic cowboy, Sheriff Woody, and modern spaceman, Buzz Lightyear.  The group unexpectedly embark on adventures that challenge and change them.

The Last Halloween: The Last Halloween is a Primetime Emmy Award-winning live action-animated Halloween television special produced by Hanna-Barbera.  It premiered and first aired on CBS on October 28, 1991.  The visual effects and animation were provided by Industrial Light & Magic and Pacific Data Images.  It was the only time Hanna-Barbera would use CGI animation insteed of traditional limited animation.

The Flintstones Meet Rockula and Frankenstone: The Flintstones Meet Rockula and Frankenstone is a 1979 animated Halloween television special featuring The Flintstones.  It was produced by Hanna-Barbera and first aired on Tuesday, October 30, 1979 on NBC.

Halli Cauthery: Halli Cauthery (full name David Harald Cauthery) is a film and television composer.  His credits include the Netflix/DreamWorks animated comedy series "Turbo F.A.S.T.", for which he received an Emmy nomination in 2016; the thriller The East (film); Bernard Rose's 2015 adaptation of Frankenstein (2015 film); the Shrek Halloween television special "Scared Shrekless"; as well as the Lifetime Television film "Living Proof".

The Devil and Daniel Mouse: The Devil and Daniel Mouse is a 1978 animated Halloween television special, from Canada's Nelvana animation studio.  It is based on the story of "The Devil and Daniel Webster".

Toy Story of Terror!: Toy Story of Terror!  is a 21-minute Halloween television special, based on the Disney Pixar "Toy Story" movies.  It is set shortly after the events of "Toy Story 3" and "Toy Story Toons", and premiered on the American television network ABC on Wednesday, October 16, 2013.  It was written and directed by Angus MacLane, produced by Galyn Susman, with Tom Hanks, Tim Allen, Joan Cusack, Don Rickles, Wallace Shawn, Timothy Dalton, and Kristen Schaal reprising their roles of Woody, Buzz Lightyear, Jessie, Mr. Potato Head, Rex, Mr. Pricklepants, and Trixie with Carl Weathers as Combat Carl and Stephen Tobolowsky as the motel manager.  Michael Giacchino composed the music for the special.  The film's soundtrack was released on October 15, 2013, on Amazon.com and iTunes in digital format.

Casper's Halloween Special: Casper's Halloween Special (also known as Casper Saves Halloween and Casper the Friendly Ghost: He Ain't Scary, He's Our Brother) is a 1979 Halloween television special produced by Hanna-Barbera featuring Casper the Friendly Ghost and his friend Hairy Scary from the animated series "Casper and the Angels".  The special was directed by Carl Urbano and premiered on NBC on October 30, 1979.

Scared Shrekless: Scared Shrekless is a 21 minute Halloween television special, set shortly after the events of "Shrek Forever After", that premiered on the American television network NBC on Thursday, October 28, 2010.

Bugs Bunny's Howl-oween Special: Bugs Bunny's Howl-oween Special is a "Looney Tunes" Halloween television special which premiered on CBS October 26, 1977.

Boo to You Too! Winnie the Pooh: Boo to You Too!  Winnie the Pooh is a Halloween television special produced by Walt Disney Television Animation and Toon City Animation, Inc. at Manila, Philippines.  Based on the Disney television series "The New Adventures of Winnie the Pooh", originally broadcast on October 25, 1996 on CBS.

Supporting paragraphs: Toy Story of Terror! Toy Story (franchise)
Answer: Pixar Animation Studios