Nickelodeon contacted Jhonen Vasquez about pitching ideas for an animated series for their older demographic and Invader Zim was the first thing he pitched. In Vasquez's words "it went from pitch to series without hardly any waiting". As the series went on, ratings declined and budgetary issues became more frequent. Before the second season was completed, Nickelodeon cancelled 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.
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