of 2008. That July they allowed fans the chance to vote between two variations of an outer box for the set—one designed to look like the main characters' firehouse headquarters and the other all black with different images on each side. Both featured lenticular printing, the firehouse version to show the Ecto-1 and the black version to have oozing "slime". Released on November 25, 2008, in the "firehouse" casing, the set spans 25 discs containing all 147 episodes of the series. They subsequently began releasing the individual volumes on March 31, 2009, but only the first three were released. Volumes 4 and 5 were not released due to poor sales. The Time Life releases have been discontinued and are now out of print. Sony began re-releasing the series on DVD in Region 1 in 2016. Volumes 1–5 (each containing 11 or 12 episodes) were released on July 5, while Volumes 6–10 (with 10 or 11 episodes each) were released on September 6. Unlike the previous Time Life edition, the Sony release is incomplete, missing 29 episodes that were inexplicably omitted, as well as the entire Slimer! sub-series. Additionally, title cards were removed from all episodes in the first five volumes (title and writer credits were superimposed over the animated opening). All 10 volumes, spanning 10 discs containing 111 episodes, were released in a slim plastic box set in October 2017 (comprising 80% of the series). The complete first season was released on DVD in Australia on June 3, 2009, and in the U.K. on June 15. Spin-offs: Extreme Ghostbusters In 1997, a sequel cartoon entitled Extreme Ghostbusters was produced by Columbia TriStar Television and Adelaide Productions. It premiered on September 1, 1997, and ran for forty episodes until its conclusion on December 8. Set several years after the end of The Real Ghostbusters, the series opened by saying the team has disbanded due to a lack of supernatural activity. Only Egon remains in the firehouse, along with Slimer, to care for the containment system while teaching classes at a local university. When supernatural events begin occurring in New York, Egon recruits four of his university students as a new team of Ghostbusters, and Janine, also one of Egon's students, returns to manage the office. The original Ghostbusters return for the two-episode season finale to celebrate Egon's 40th birthday, leading to them reluctantly working together with the younger generation to solve