ThunderCats (1985 TV series)

The basic plot above holds strong for the first season of the show, and served as the basis for a vast array of stories that freely mixed elements of science fiction and fantasy into a traditional good-versus-evil tale that steadily introduced more and more recurring allies and villains into the world of the ThunderCats. Futuristic technology is just as central to the series as magic and myth, but even in the midst of all this action, the series never underemphasizes the importance of moral values in solving problems. Each episode would normally include a short dénouement, featuring the characters recuperating after the events of the story and taking the time to single out a personal value or wholesome approach that helped save the day, or could have done so if they had seen it.

The first half of Season 1 featured a gentle continuity, with early episodes following on from one another and establishing recurring concepts, although this became less common as the season transitioned into its second half, which comprised mostly incidental one-shot adventures. Tying the second half of season one together was the overarching five-part adventure written by series head writer Leonard Starr, "Lion-O's Annointment", in which an unarmed Lion-O faced off against first each of the other ThunderCats, and then Mumm-Ra, so he could truly earn his title as Lord of the ThunderCats. The five parts were:

1. "Day One: The Trial Of Strength" – Lion-O had to out-do Panthro in a strength contest.
2. "Day Two: The Trial Of Speed" – Lion-O had to beat Cheetara in a race.
3. "Day Three: The Trial Of Cunning" – Lion-O had to outwit both of the "ThunderKittens", WilyKat and WilyKit, in an underground location.
4. "Day Four: The Trial Of Mind-Power" – Lion-O was pitted against Tygra in a mind-based challenge.
5. "Last Day: The Trial Of Evil" – Lion-O had to defeat Mumm-Ra. In his "Trial Of Evil", Lion-O discovered that Mumm-Ra was highly dependent on the sarcophagus inside which he had been mummified.

On all four days except the last, the Mutants tried to interfere with Lion-O's trials so that they could force the ThunderCats to remain leaderless. The other ThunderCats were each then forced to involve themselves in the conflict specifically to foil the Mutants's interferences—all while trying to avoid assisting Lion-O in his anointment trials.

Although intended to be viewed consecutively (as the adventures depicted occurred one day after the other), the five parts of the mini-series were erroneously aired (and released on DVD) with multiple other episodes between each instalment.

The 1986 TV movie ThunderCats – Ho! featured the first major shake-up to the status quo of the series, introducing three new Thundereans (whom Lion-O later anointed as ThunderCats) who had also survived the destruction of Thundera. A massive cast of returning heroes and villains were incorporated into the story and concluded with the apparent destruction of Mumm-Ra. Leonard Starr wrote the story for this TV movie. ThunderCats – Ho! was then split into five installments, becoming the initial episodes of season two.

When the series returned in 1987, it was revealed that the evil wizard Mumm-Ra had survived. "ThunderCats – Ho!" and its follow-up, "Mumm-Ra Lives!", set the pattern for the following three seasons, each of which began with a five-part mini-series—again written by Leonard Starr—that established the new characters and concepts that would go on to influence the rest of the season. In the case of "Mumm-Ra Lives!", these concepts included the debut of the villainous Lunataks, which became a third faction that existed for the rest of the series, and the new team of ThunderCats from ThunderCats – Ho! receiving their own headquarters and vehicles.

The 1988 season began with the Peter Lawrence-scripted "ThunderCubs" which, though named for its plot about the ThunderCats being transformed into children, was principally about Mumm-Ra reconstructing Thundera in order to retrieve both the weapon that had originally destroyed it (the Sword of Plun-Darr) and the legendary Treasure of Thundera. In the course of the adventure, the treasure—containing the Book of Omens, a tome holding all the secrets of the ThunderCats, and many other mystical items—was scattered across the New Thundera, ushering in a new concept for the series: a season with an actual story arc. Continuity between episodes became tighter as the ThunderCats, Mutants, Lunataks and Mumm-Ra alternated their adventures between Third Earth and New Thundera, searching for the treasure and exploiting its powers. The season also featured the running theme of the Ancient Spirits of Evil having to take a more active hand in pushing Mumm-Ra into action, culminating in another unique feature of the season—an actual finale episode, "The Last Day", in which the Ancient Spirits of Evil give Mumm-Ra one last chance to destroy the ThunderCats by sunset. Besides demonstrating their threat by making Ma-Mutt disappear, the Ancient Spirits of Evil stated that Mumm-Ra's failure will also have the Mutants and the Lunataks removed from Third Earth as well. Ultimately, Mumm-Ra failed and the Ancient Spirits of Evil exiled him to the farthest corner of the Universe.

In the opening miniseries, Peter Lawrence's "Return to Thundera!", the ThunderCats returned to New Thundera to rebuild their society, but before departing, they destroyed Mumm-Ra's pyramid. This enraged the Ancient Spirits of Evil to the point that they brought Mumm-Ra back and installed him within a new pyramid on New Thundera. The season proved to be quite divorced from what had gone before, with adventures consigned almost entirely to New Thundera, and most villainous opposition coming from either Mumm-Ra or assorted new villains. The Mutants, Lunataks, and Captain Cracker all returned for one episode each. However, in the series finale, several conclusions are reached:

• Mumm-Ra stands up to and successfully asserts himself over the Ancient Spirits of Evil.
• The mystery of the Book of Omens is at last solved.
• The tumultuous and terrifying environment of Thundera is at last rendered peaceful and pristine.

Warner Home Video/Warner Bros. Family Entertainment released the entire original 1980s series of ThunderCats in the US over a number of volumes in the following order:

Warner Home Video have released the entire ThunderCats series in the UK in the following order:

On 16 November 1987, a VHS called 'Thundercats Ho!' was released in the UK by Video Collection International. The film was submitted to the BBFC, who recorded it being 90 m 31s excluding 5 seconds cut for a Universal rating. It was actually the first five episodes of season 2 edited to look like a feature-length film. Season 2 never aired in the UK. This VHS may have been shown on American TV by stations without access to the individual episodes.

In 2008–2009, Warner Bros. was in the process of creating a CGI animated film based on ThunderCats. It was rumored to be an original story expanding on the events of the first episode and the film's concept artwork (released in July 2009) contained the main character Lion-O and three locations. A two-minute test scene was filmed and presented to Warner Bros.; however, the movie has been put on indefinite hold, perhaps due to the critical and commercial failure of the 2008 movie Speed Racer (another Warner Bros. CGI project).

In March 2021, it was announced that Warner Bros. was once more actively developing a live-action ThunderCats film with Adam Wingard attached to direct the film, with a screenplay by Wingard and Simon Barrett, and Roy Lee and Dan Lin serving as producers.[24]

A new ThunderCats animated series produced by Warner Bros. Animation began airing on Cartoon Network from July 2011.[25] Animation production was provided by Japanese animation studio Studio 4°C. Sam Register was the executive producer and was joined by Michael Jelenic and Ethan Spaulding as the producers for the series.[26] The show explained Lion-O's ascension to the Thunderean throne with a more original feel and darker style than the 1980s series. The new series made it clear in the very beginning, however, that they are not adhering to the original story line. In the original series the Thunder Cats leave Thundera, as the last of their race, to eventually arrive on the 3rd earth. In the new series the very first line states that the Thundereans are already on the 3rd earth. As the first few episodes progress the new writers seem to use Thundera but it isn't clear if they are referring to a planet or kingdom.[27] Former Lion-O voice actor Larry Kenney returned to play the role Lion-O's father Claudus in the opening two-part episode of the new series.[28]

In January 2011, a promotional poster featuring re-imagined designs for Lion-O, Cheetara, Panthro, and Tygra as well as design for the Sword of Omens and vehicles were shown at the London Toy Fair.[29] The series began airing on Cartoon Network on July 29, 2011 with an hour-long premiere,[30] while the UK premiere on Cartoon Network began on 10 September the same year.[31]

Despite an early positive response (with the animation in particular receiving heavy praise from critics), the series failed to make any real impact and viewing figures slowly declined after the first episode, with blame falling on a relatively dark and complicated storyline considering the show was aimed at 6-12 year olds. Merchandise struggled to sell, and as a result the show was cancelled after only one season.

There were also several comic book series produced. A ThunderCats comic book series based on the animated series was originally published by Marvel Comics through its Star Comics imprint in 1985, lasting for 3 years and 24 issues.[32] During this time, a new series was published by Marvel UK consisting of 129 issues and was also published for three years.[33] Beginning in 2002 ThunderCats titles were published by Wildstorm Productions, an imprint of DC Comics (Warner Bros.' corporate sibling), and included 5 non-canon mini-series and several one-shots.[34]

Two video games based on the franchise exist: ThunderCats: The Lost Eye of Thundera, a 1987 side-scrolling video game; and ThunderCats, a 2012 Nintendo DS game based on the show's revival.