Invader Zim is an American animated dark comedy science fiction television series that was created by comic book writer and cartoonist Jhonen Vasquez and aired on Nickelodeon. The series revolves around an extraterrestrial named Zim (voiced by Richard Steven Horvitz) from the planet Irk and his ongoing mission to conquer or destroy a dark and satirical version of the Earth. His various attempts to subjugate and destroy the human race are invariably undermined by some combination of his own ineptitude, his malfunctioning robot servant GIR (Rosearik Rikki Simons) and his nemesis Dib (Andy Berman), one of very few humans not oblivious enough to be unaware of Zim's identity. Invader Zim premiered on March 30, 2001. The series was targeted at older children and adolescents and met with critical acclaim. As the series went on, ratings declined and budgetary issues became more frequent. Before the second season was completed, Nickelodeon canceled the series, leaving several episodes unfinished. The show originally ran on Nickelodeon from 2001 to 2002, with six of the completed second-season episodes initially going unreleased. These episodes were first made available on DVD in 2004 and later made their television debut on the Nicktoons Network in 2006. Despite its early cancellation, due to increasing popularity and above-average merchandise sales, it has been widely regarded as a cult classic. The series consists of a pilot episode, twenty-seven episodes split into forty-six episode segments, and at least seventeen unfinished episode segments that were in production at the time of the series' cancellation. On December 24, 2011, the pilot episode aired on television for the first time. Thirty-eight episode segments were originally broadcast in pairs, each 12-minute episode segment debuting in the same half-hour. There are eight double-length episodes which run for 24-minutes each. This list is ordered by the episode order in the DVD releases, with broadcast dates noted. Every episode was directed by Steve Ressel; except the pilot, which was directed by Jordan Reichek. A television film based on the series, entitled Invader Zim: Enter the Florpus, premiered August 16, 2019 on Netflix. Series overview Episodes Pilot A pilot for Invader Zim was produced for Nickelodeon in 1999, featuring Billy West as the voice of Zim. However, because he was too busy with Futurama at the time, West was replaced by Richard Steven Horvitz in the series proper. It was first released publicly as a special feature on the Invader