The Season 1 that changed everything
In 1985, animated television experienced a revolution. On January 23 of that year it was broadcast for the first time "Exodus", the pilot episode of ThunderCats, and nothing was ever the same. With 65 episodes spread throughout that year, the first season of the Rankin-Bass series established a universe so rich, such memorable characters, and such a powerful mythology that decades later we are still talking about it. Lion-O He went from being a child trapped in an adult's body to becoming the Third World's most legendary warrior, all in the course of those founding episodes.
Season 1 not only introduced the main characters—from the speedy Cheetara to the ingenious Tygra—but built an entire cosmology: the destroyed planet Thundera, the Third World as a new home, the Cat Castle as a bastion of hope, and the black pyramid of Mumm-Ra as a source of eternal darkness. This guide takes you through the ten most brilliant episodes of that first season, those that defined why ThunderCats is much more than just a cartoon.
The 10 essential episodes
🥇 #1 — "Exodus" (Episodes 1 and 2, January 23, 1985)
The absolute beginning. Thundera explodes, the ThunderCats flee through space in a spawn ship, the Mutants attack them, Jaga sacrifices his life to guide the survivors, and Lion-O awakens with the body of an adult but the mind of a child. In their new home—the Third World—the ThunderCats must survive, build the Cat Castle, and face an unknown enemy even more dangerous than the Mutants: Mumm-Ra. This double episode is cinematic in ambition, emotionally devastating in its execution, and technically impressive for television animation of the time. No fan of the series can afford not to have seen it.
🥈 #2 — "The Unholy Alliance" (Episode 2, second part of the pilot)
Mumm-Ra bends the Mutants to his will in the black pyramid. It is the moment when the series makes it clear that the true villain is not the clumsy Mutants but an entity of pure, ancient evil. Mumm-Ra's first transformation—from decrepit mummy to immortal warrior—is one of the most iconic moments in 80s animation. "By the dark spirits of evil, transform, Mumm-Ra, the eternal!" The voice acting and animation create something genuinely scary for a children's show.
🥉 #3 — "The Berbils" (Episode 3)
The ThunderCats meet their first allies in the Third World: the Ro-Bear Berbils, pacifist robotic bears who are enslaved by the Conquerors. This episode sets the pattern for the series: the Third World is full of civilizations that need protection, and the ThunderCats are their natural defenders. The Berbils become essential allies, builders of the Cat Castle and the ThunderCats vehicles. An endearing episode that establishes the moral heart of the series.
#4 — "The Slaves of Plun-Darr Castle" (Episode 4)
The Mutants enslave the Brutemen to build their fortress. Lion-O leads a rescue mission but the Mutants have traps prepared. This episode shows for the first time the tactical tension that would characterize the series: brute force is not enough, you have to think. It is also the debut of Castle Plun-Darr as a seat of evil in the Third World, a dark counterpoint to the luminous Cat Castle.
#5 — "Pumm-Ra" (Episode 11)
Mumm-Ra disguises himself as an injured ThunderCat to infiltrate the Cat Castle and steal the Sword of Omens. It is the first major espionage and infiltration episode of the series. The fact that Mumm-Ra can take any form turns each new character into a potential threat, adding a layer of paranoia that enriches the narrative. The scene in which the Sword alerts Lion-O of the deception is an absolute classic.
#6 — "The Phantom Warrior" (Episode 12)
A forgotten sarcophagus in the Third World releases the spirit of Grune the Destroyer, a former ThunderCat who betrayed his order and was sealed away. It is the first episode to explore Thundera's dark past and demonstrate that not all ThunderCats are noble: Grune's fall for ambition is a sophisticated, adult theme. The animation of his ghostly form and the background music make it one of the most atmospheric episodes of the entire season. IMDb: 7.9/10.
#7 — "Safari Joe" (Episode 38)
The most successful hunter in the galaxy arrives in the Third World with one goal: capture ThunderCats as trophies. This episode is pure high-octane entertainment: a charismatic villain, genuinely tense situations, and a clever denouement that depends not on strength but on wit. Safari Joe is one of the best single-episode villains in the entire series, and his confrontation with Lion-O is among the most exciting of the year. IMDb: 7.9/10.
#8 — "The Eight-Legged Queen" (Episode 39)
Mumm-Ra uses a powerful spider queen to trap the ThunderCats in his deadly web. Visually spectacular, this episode stands out for the scale of the threat and the way the team must coordinate to survive. It is also one of the episodes that best shows the individual abilities of each ThunderCat working together, something that the series always did brilliantly but that reaches one of its best expressions here.
#9 — "Lion-O's Coronation Day — Trial of Strength" (Episode 55)
The first of the five Coronation Trials is perhaps the most exciting: Lion-O must face Panthro, the strongest ThunderCat, without using the Sword of Omens. The premise—that the ThunderCats themselves must oppose their leader—revers the usual dynamic in a fascinating way. The fight is tough, honest, and ends in a way that says a lot about Lion-O's character. IMDb: 8.0/10.
#10 — "Final Coronation Day: The Judgment of Evil" (Episode 61)
The climax of the Coronation Trials: Lion-O must face Mumm-Ra alone, without the Sword of Omens, without his companions. It is the highest episode of the first season in narrative quality and the one that best captures Lion-O's character arc from the pilot's insecure boy to the true Lord of the ThunderCats. The fight is epic, the outcome is satisfying, and the message about the true meaning of leadership is powerful. IMDb: 8.2/10, the most voted of the season.
Key facts from Season 1
| Fact | Information |
|---|---|
| Total episodes T1 | 65 episodes (the 65 with the highest production quality of the series) |
| Start date | January 23, 1985 — Episode 1: "Exodus" |
| End date | December 20, 1985 |
| Best narrative arc | The 5 Coronation Trials of León-O (Eps. 55–61) |
| highest rated episode | "Final Day: The Judgment of Evil" — IMDb 8.2/10 |
| Producers | Rankin-Bass Productions / Lorimar-Telepictures |
7 Curiosities from Season 1
- The first five episodes of the series were edited and released as a movie called "ThunderCats — Exodus: The Movie" for home video distribution in several countries.
- The pilot episode "Exodus" He didn't have the battle cry "ThunderCats, get up!" in its first broadcast; It was added later when the series format was established.
- The animation for Season 1 was mainly done by the Japanese studio Pacific Animation Corporation (PAC), which later became part of Walt Disney Television Animation.
- Grune the Destroyer, protagonist of episode 12, is one of the few ThunderCats characters whose name directly references a real ThunderCat fallen from grace, adding historical depth to the universe.
- Safari Joe (episode 38) was so popular with fans that his name is regularly mentioned in lists of the best single-episode villains from 1980s cartoons, alongside antagonists from He-Man and G.I. Joe.
- The five Coronation Trials of Lion-O were conceived as a stand-alone arc that could air at any point in the season; they were finally placed towards the end to maximize the cumulative dramatic impact of the first season.
- The episode "The Unholy Alliance" established that Mumm-Ra always runs away when he sees his own reflection—a weakness that the ThunderCats will exploit repeatedly throughout the entire series and which originated from the characteristics of the mummy-man myth in pop culture.
In the 2026 Movie
The universe that was born in these 65 episodes of Season 1 is about to jump to the big screen. Amazon Studios and Warner Bros. have the live-action ThunderCats movie in development, directed by Adam Wingard (Godzilla x Kong: The New Empire). Wingard has made it clear that his vision respects the legacy of the original series: "It's not going to look like Cats. This is going to look like ThunderCats." All the elements that made Season 1 great—the epicness of the pilot, the depth of the characters, the struggle between light and darkness—are exactly the kind of material that could work brilliantly in 21st-century cinema.
What is your favorite episode of ThunderCats Season 1? Do you agree with this top 10 or do you think there are any episodes that deserved to be on the list? Leave us your opinion in the comments and share this article with all fans of cosmic cats. ThunderCats, get up!
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⚡ FREQUENTLY ASKED QUESTIONS ⚡
What should you know about: The Season 1 that changed everything?
In 1985, animated television experienced a revolution. On January 23 of that year it was broadcast for the first time "Exodus" , the pilot episode of ThunderCats, and nothing was ever the same. With 65 episodes spread ...
What should you know about: The 10 essential episodes?
🥇 #1 — "Exodus" (Episodes 1 and 2, January 23, 1985) The absolute beginning. Thundera explodes, the ThunderCats flee through space in a spawn ship, the Mutants attack them, Jaga sacrifices his life to guide the ...
What should you know about: Key facts from Season 1?
The first five episodes of the series were edited and released as a movie called "ThunderCats — Exodus: The Movie" for home video distribution in several countries. The pilot episode "Exodus" He didn't have the battle ...
What should you know about: 7 Curiosities from Season 1?
The first five episodes of the series were edited and released as a movie called "ThunderCats — Exodus: The Movie" for home video distribution in several countries. The pilot episode "Exodus" He didn't have the battle ...
What should you know about: In the 2026 Movie?
The universe that was born in these 65 episodes of Season 1 is about to jump to the big screen. Amazon Studios and Warner Bros. have the live-action ThunderCats movie in development, directed by Adam Wingard (Godzilla x ...
