The following is an episode list for the Rankin/Bass animated television series ThunderCats. The pilot was shown on January 23, 1985, following which the series series began on September 12, 1985, running until 1989 for 130 episodes.

Season 1 comprises 65 episodes - a standard number for animated series at the time, as it allowed the series to be shown every weekday for thirteen weeks (one full broadcast season). In 1986, the series returned for a TV movie, "ThunderCats - Ho!", which was subsequently aired as five separate episodes worked into the continuing rerun rotation of Season 1. Beginning in 1987, the show adopted a pattern of a season of twenty new episodes per year, each season beginning with a five-part miniseries that established the new concepts and characters that would play into the events of the season that followed. For whatever reason, however, most online episode guides for the series mistakenly claim that the series only aired in two seasons of 65 episodes, concluding in December 1986, despite the fact that the years of release for the post-Season 1 episodes are clearly presented in the copyright details at the end of the credits as 1986 through 1989.

The entire series has been released on DVD, collecting season 1 across two box-sets, with the remaining 65 episodes spread out over two further sets (misleadingly labeled as "Season 2, Volume 1" and "Season 2, Volume 2", not helping to dispel the internet-borne misconception about the show's season structure). Season 1, Volume 1 was recalled when it was discovered that the second episode was missing its background musical score, and a corrected version was released in its place. Volume 1 was released on August 9, 2005 and volume 2 on December 6, 2005.

The list below presents the episodes in their original broadcast order, which is also the order used for the DVD release of the series. However, neither this order nor the original production order of the episodes is the correct chronological story order for the series. Although there is little in the way of major continuing storyline running through ThunderCats, certain creatures reoccur and clips from other episodes are employed. At times, the order used below causes these to be presented out of order. This is only a problem in the second half of season 1, and especially affects the five episodes which comprise the mini-series Lion-O's Anointment, which are split up throughout the latter half of the season, when the stories featured are supposed to occur on consecutive days.

Pilot (1985)

Title Writer Original airdate Production code #
Exodus Leonard Starr January 23, 1985 1 1
The Thundercats must find a new home after their home planet, Thundera, explodes. Their journey changes when an enemy known as the Mutants attack and leaves their ship severely crippled. And a young boy must learn what it means to become a man and Lord of the Thundercats as he learns to wield the power of the Sword of Omens.[1]
The Unholy Alliance Leonard Starr January 23, 1985 2 2
While exploring Third Earth, the Mutants ship is brought down by a mysterious black pyramid which is the home to Mumm-Ra, an evil demon who is willing to form an allegiance to capture the Eye of Thundera.[2] With the young Lord of the Thundercats in sight, Lion-O is about to face his toughest enemy yet.

Season 1 (1985)

Title Writer Original airdate Production code #
Berbils Leonard Starr September 11, 1985 3 3
While out exploring, Lion-O and Snarf are taken prisoner by a band of small robotic bears named Ro-Bear Berbils.[3] They soon learn that the Berbils are being frequently attacked by the Trolligs[4] who steal their fruit to give to the Giantorrs.[5]
The Slaves of Castle Plun-darr Leonard Starr September 12, 1985 4 4
Cats Lair[6] is nearly complete when an agitated Wilykit and Wilykat rush home to tell the other ThunderCats that the Mutants have enslaved a race of creatures called Brute Men to build their new fortress. Tygra tells the twins to stay behind as the adult ThunderCats rush off to free these peaceful creatures.
Pumm-Ra Julian P. Gardner September 13, 1985 5 5
Mumm-Ra disguises himself as a Thunderian and claims to have rescued Cheetara from the mutants.
The Terror of Hammerhand Ron Goulart and Julian P. Gardner September 16, 1985 6 6
Snarf frees a unicorn from mechanized Viking berserkers who are out hunting for food.
Trouble with Time Ron Goulart and Julian P. Gardner September 17, 1985 7 7
The mutants are looking for a "feminine touch" around Castle Plundar and attempts to capture natives of the 3rd Earth. Willa and her sister fights off Monkian, but both of them are cautious of the aliens (i.e. Thundercats & the Mutants). Lion-O also takes the Thundertank for a "shortlived" joyride. Whilst looking for Thundrylium[7] in a cave Tygra begins to age at an accelerated rate.
The Tower of Traps Leonard Starr September 18, 1985 8 8
In search of a piece of stolen jewellery, Wilykat becomes a prisoner locked up in a tower as Lion-O and Wilykit must find their way to him through a maze of booby traps.
The Garden of Delights Barney Cohen and Julian P. Gardner September 19, 1985 9 9
Mumm-Ra drugs Tygra and uses him against his fellow ThunderCats to steal the Sword of Omens making them vulnerable as Mumm-Ra soon takes them prisoner.
Mandora - The Evil Chaser William Overgard September 20, 1985 10 10
Lion-O finds what looks like a spaceship's escape pod, he opens it and inadvertently releases galactic convicts.
The Ghost Warrior Leonard Starr September 23, 1985 11 11
Two Bulkans[8] release the ghost of Grune the destroyer from his tomb, he seeks a final battle with Jaga.
The Doom-Gaze Stephen Perry September 24, 1985 12 12
The ancients spirits of evil instruct Mumm-Ra to release an ancient princess who has the power to mesmerise males with her gaze.
Lord of the Snows Bob Haney September 25, 1985 13 13
A meteor of pure Thundrylium[7] crashes into the remote Hook mountain. When Lion-O goes after it, he finds himself face to face with a man of the mountain whom he must fight. This is also the first appearance of Vultureman.
The Spaceship beneath the Sands Leonard Starr September 26, 1985 14 14
After repeated defeats the mutants ask Mumm-Ra to return their ship which he buried in the desert around his pyramid. Once it is resurfaced, they have new weapons to use against the ThunderCats.
The Time Capsule Peter Lawrence September 27, 1985 15 15
The ThunderCats decide it is time to search for their time capsule from Thundera which has been missing since the crash.
The Fireballs of Plun-Darr William Overgard September 30, 1985 16 16
The warrior women's village is attacked by Fireballs from a new weapon inside Castle Plun-Darr. When Tygra goes to investigate, he is captured and locked into a device which will rip him apart by pulling out his four limbs.
All That Glitters Bob Haney October 1, 1985 17 17
Mumm-Ra tricks Lion-O and Tygra into fighting each other which causes the Sword of Omens to break. In order to repair it the ThunderCats seek the help of a being whose powers are derived from bathing in liquid gold.
Spitting Image Howard Post October 2, 1985 18 18
After the driller captures Panthro, Mumm-Ra creates an evil clone of him to turn the people of Third Earth against the ThunderCats.
Mongor Peter Lawrence October 3, 1985 19 19
While exploring, the ThunderKittens stumble across an old temple where their curiosity gets the best of them and they release a demon. It's a goat-like creature who gets more powerful as others fear him. It's up to the Thundercats to find a way to overcome their fears and defeat this monster.
Return to Thundera Bob Haney October 4, 1985 20 20
The Mutants unleash a new invincible war robot while Lion-O accidentally travels back in time to Thundera after the eye of Thundera reacts with the Thunderian time capsule. There he meets his father, Claudius, who gives him a scroll containing a Mutant secret.
Dr. Dometone William Overgard October 7, 1985 21 21
A frog robot swallows Wilykit. It turns out to be piloted by Dr. Dometome the scientist responsible for maintaining the ocean's plug which stops the ocean draining into the Earth's core.
The Astral Prison Peter Lawrence October 8, 1985 22 22
Jaga is imprisoned within the astral plane for eternity. Lion-O must journey there to release him, however there is no way for him to return.
The Crystal Queen Leonard Starr October 9, 1985 23 23
A rare and beautiful bird is captured by the Queen of a crystal kingdom.
Safari Joe Stephen Perry October 10, 1985 24 24
Safari Joe comes to Third Earth looking for prey 'worthy' of being hunted. He begins hunting the ThunderCats.
Snarf Takes up the Challenge Peter Lawrence October 11, 1985 25 25
After the ThunderCats are captured by Mumm-Ra, it is up to Snarf to save them.
Sixth Sense Peter Lawrence October 28, 1985 26 26
A ship in trouble tries to ask the ThunderCats for help using Cheetara's sixth sense. It ends up taking control of Cheetara and putting her life in danger as the mutants attack it.
The Thunder-Cutter William Overgard October 29, 1985 27 27
Mumm-Ra summons Haichiman a samurai from ancient times, and tells him the ThunderCats are evil invaders. Haichiman sets out to destroy them.
The Wolfrat C.H. Trengove October 30, 1985 28 28
Vultureman builds an infiltration robot and Mumm-Ra arms it with miniturisation gas which then shrinks the ThunderCats. They must rely on a normal size Snarf to help them defeat the robot.
Feliner - Part 1 Stephen Perry October 31, 1985 29 29
Vultureman summons Rattaro and his Ratstar battleship who kidnaps Snarf's nephew Snarfer on the planet of Snarfs. They then bring Snarfer back to Third Earth and use him as bait to trap the ThunderCats.
Feliner - Part 2 Stephen Perry November 1, 1985 30 30
The ThunderCats race to try to salvage the part they need for the Feliner from the wreck of the Ratstar before the mutants can complete repairs. Snarf contemplates leaving the Thundercats forever.
Mandora and the Pirates William Overgard November 4, 1985 31 31
Mandora boards a space freighter for inspection, it turns out to be the ancient space pirate ship the Jolly Rogers and she needs Lion-O's help.
Return of the Driller Howard Post November 5, 1985 32 32
Mumm-Ra instructs the Driller to bore a tunnel from an acid lake to the Cats Lair. It's a race to save the Lair as they face obstacle after obstacle while trying to obtain and bring back a sponge cloud to fill the hole.
Dimension Doom Bob Haney November 6, 1985 33 33
Wizz-Ra returns from the 7th dimension once every 7000 years, this time he enters Cat's Lair through a mirror in Cheetara's room. Mumm-Ra, his ancient enemy, is able to steal his magic helmet. He then enslaves the Thundercats and only Cheetara and Snarf are left to help their new friend before his time runs out.
Queen of 8 Legs Stephen Perry November 7, 1985 34 34
In the kingdom of webs a new queen is born, Mumm-Ra lures Lion-O to the kingdom and the spiders trap him.
Sword in a Hole William Overgard November 8, 1985 35 35
The ThunderCats respond to a space liner's SOS only to be captured by mercenaries on Mumm-Ra's pay. The Sword of Omens is cast into a black hole.
The Evil Harp of Charr-Nin Douglas Bernstein and Denis Markell November 11, 1985 36 36
Wilykit and Wilykat find a magic harp containing a genie. Mumm-Ra offers to free the genie if he helps to destroy the ThunderCats.
*Lion-O's Anointment First Day: Trial of Strength Leonard Starr November 12, 1985 37 37
Snarf tells Lion-O that he must earn his title as Lord by completing five trials, the first of which will be to defeat the mighty Panthro.
The Demolisher Bob Haney and Peter Lawrence November 13, 1985 38 38
A bored galactic conqueror comes to Third Earth to battle Mumm-Ra. After defeating Mumm-Ra and hearing of the ThunderCats power he rushes off to battle Lion-O.
Monkian's Bargain Lee Schneider November 14, 1985 39 39
Monkian makes a deal with Mumm-Ra to give him power orbs whatever the cost.
Tight Squeeze Stephen Perry November 15, 1985 40 40
After a disagreement Vultureman leaves castle Plun-darr and destroys all the mutants technology. Slithe is forced to ask Mumm-Ra to take away the ThunderCats' weapons which he seals within the sword chamber so that the ThunderCats cannot reach them.
The Micrits Bruce Smith November 18, 1985 41 41
Lion-O is captured by very small creatures who see him as a threat to their village, and disable Cats Lair and the Thundertank. The Mutants seize the opportunity and wreak havoc on the other Thundercats who don't know where Lion-O is.
*Lion-O's Anointment Second Day: The Trial of Speed Leonard Starr November 19, 1985 42 42
Lion-O must beat Cheetara in a race to pass the second anointment trial.
The Rock Giant Peter Lawrence November 20, 1985 43 43
Mumm-Ra awakens a monster made of rocks to defeat the ThunderCats.
Jackalman's Rebellion Bruce Smith November 21, 1985 44 44
Jackalman forms his own army and steals weapons from the Mutants.
Turmagar the Tuska C.H. Trengove November 22, 1985 45 45
A strange traveller crash lands next to Cats Lair, he enlists the ThunderCat's help to battle a war machine.
*Lion-O's Anointment Third Day: Trial of Cunning Leonard Starr November 25, 1985 46 46
Lion-O must outwit Wilykit and Wilykat in the Maze of Infinity but there are more than ThunderKittens lurking about who are ready to stop him.
The Mumm-Ra Berbil Jeri Craden November 26, 1985 47 47
Mumm-Ra disguises himself as an injured Ro-Bear Berbil[3] to infiltrate Cats Lair.
Mechanical Plague Peter Lawrence November 27, 1985 48 48
Mumm-Ra takes advantage of the ThunderCats being separated as they make their own home movies. He summons the greatest mechanical adversaries in an attempt to destroy them.
Trapped Stephen Perry November 28, 1985 49 49
Sheltering from a storm inside an old Suspension Capsule,[9] Wilykit and Wilykat become trapped. Things take a turn for the worse when the Mutants find out about it.
*Lion-O's Anointment Fourth Day: The Trial of Mind Power Leonard Starr November 29, 1985 50 50
Lion-O must overcome Tygra's mental powers and face his greatest fear.
Excalibur Peter Lawrence December 2, 1985 51 51
Mumm-Ra takes the form of King Arthur in order to claim the greatest sword of all time, Excalibur so that he can finally destroy the Sword of Omens.
Secret of the Ice King Bob Haney December 3, 1985 52 52
An Ice King who has been frozen for 1,000 years is suddenly awakaned and is wreaking havoc on Hook Mountain.
Good and Ugly Peter Lawrence December 4, 1985 53 53
Two aliens arrive in spaceships and fight near Cats Lair and Lion-O must learn a lesson about first impressions.
The Transfer Lawrence DuKore and Lee Schneider December 5, 1985 54 54
An unknown ship containing a dangerous radioactive device approaches Third Earth.
Divide and Conquer Lee Schneider December 6, 1985 55 55
Vultureman creates a voice imitator and the Mutants use it to trick the ThunderCats into splitting up to trap and destroy them.
Dream Master Heather Winters and Annabelle Gurwitch December 9, 1985 56 56
Mumm-Ra assumes the form of a Dream Master to take control of the ThunderCats unconscious selves.
Out of Sight C.H. Trengove December 10, 1985 57 57
Willa is captured by the mutants so Tygra makes himself and Nayda invisible to infiltrate castle Plun-darr not knowing the consequences.
The Mountain Danny Peary December 11, 1985 58 58
Out of sheer boredom Lion-O climbs a mountain. The mutants decide to attack putting themselves and the ThunderCats in danger.
The Superpower Potion C.H. Trengove December 12, 1985 59 59
Vultureman creates a potion that grants the drinker super powers.
Eye of the Beholder Kenneth E. Vose December 13, 1985 60 60
The ThunderCats create a fake Sword of Omens and use it to trick the mutants, the plan backfires when Snarf is captured.
*Lion-O's Anointment Final Day: The Trial of Evil Leonard Starr December 16, 1985 61 61
Lion-O must defeat his greatest enemy, Mumm-ra, to complete the trials.
The Trouble with ThunderKittens Kimberly B. Morris December 17, 1985 62 62
Eager to prove that they are old enough for adult weapons, Wilykit and Wilykat sneak off with the adult Thundercats weapons for some practice. The Mutants seize an opportunity and the kids escape, but the weapons are now in the hands of the Mutants and the kids will have to confess to Lion-O what they did to gain his help in retrieving them.
Mumm-Rana Bob Haney December 18, 1985 63 63
After a space battle the Mutants' escape pods land next to a white pyramid. Inside they meet Mumm-Rana who is the good equivalent of Mumm-Ra. Mumm-Ra arrives and takes control of her to use her power against the ThunderCats.
The Shifter Matthew Malach December 19, 1985 64 64
Vultureman builds a device that switches the consciousness of two beings and takes aim at the ThunderCats.
Fond Memories Lee Schneider December 20, 1985 65 65
Mumm-Ra creates a 'living' museum of the ThunderCats' greatest enemies and traps Lion-O. But his most formidable enemy is one he's not yet fought.

TV movie (1986)

Title Writer Original airdate Production code #
ThunderCats - Ho! Part I Leonard Starr September 8, 1986 66 66
Recurring nightmares of Thunderians killed on Thundera as he fled to safety with Jaga and the other ThunderCats awaken Lion-O. Jaga comes to tell him that they in fact survived and are living on Third Earth. After meeting with the other ThunderCats, they decide to begin searching for them but Mumm-Ra has plans as well.
ThunderCats - Ho! Part II Leonard Starr September 9, 1986 67 67
Lion-O's rescue attempt fails and the captured Thunderians are taken to Fire Rock[10] Mountain after another failed attempt on their part to break free from their captors.
ThunderCats - Ho! Part III Leonard Starr September 10, 1986 68 68
Lion-O loses the Sword of Omens in an avalanche. Panthro battles the Fist-Pounder with the ThunderTank. The Mutants arrive at Fire Rock Mountain to take control of the prisoners.
ThunderCats - Ho! Part IV Leonard Starr September 11, 1986 69 69
The Thunderians attempt to escape their prison. Lion-O arrives at Fire Rock[10] Mountain and is confronted by Hachiman who believes Lion-O is causing the suffering of his ancestor.
ThunderCats - Ho! Part V Leonard Starr September 12, 1986 70 70
Lion-O and Hachiman are reconciled and the ThunderCats close in on rescuing the Thunderians from Fire Rock[10] Mountain. But they'll need supernatural help if they are to pass through the Thundranium gasses to reach them.

Season 2 (1987)

Title Writer Original airdate Production code #
Mumm-Ra Lives! Part I Leonard Starr September 15, 1986 71 71
Mumm-Ra is weak and he faces the threat of three new ThunderCats, so he sends the Mutants to release his old enemies the Lunatacs imprisoned in Dark Side[11] in order to bolster the forces of evil. The ThunderCats celebration of their victory over Mumm-Ra and the welcoming of three new ThunderCats is cut short when Snarf overhears plans at Castle Plundarr after he chased Ma-Mutt there from the Berbil village.
Mumm-Ra Lives! Part II Leonard Starr September 16, 1986 72 72
The Mutants succeed in releasing the Lunatacs. The ThunderCats discover their Thundrylium[7] mine is being looted and people are being kidnapped from the villages. Lion-O and the ThunderKittens have their first run-in with a Lunatac and Bengali's skills as a blacksmith come in handy.
Mumm-Ra Lives! Part III Leonard Starr September 17, 1986 73 73
The ThunderCats build the Tower of Omens to monitor for Sky Tomb which will be run by the new ThunderCats. Ma-Mutt disguised as a Berbil[3] spies on the ThunderCats plans and the Lunatacs are sent to destroy the Tower. Snarfer contacts Snarf to tell his uncle that he's coming to Third Earth.
Mumm-Ra Lives! Part IV Leonard Starr September 18, 1986 74 74
Mumm-Ra's power is restored. Snarfer makes it to Third Earth but crashes in Dark Side and the ThunderCats rush to his aid before the Lunatacs can get ahold of him.
Mumm-Ra Lives! Part V Leonard Starr September 19, 1986 75 75
The ThunderCats look for Sky Tomb to free the slaves imprisoned inside it. Bengali must learn the importance of teamwork as Lion-O leaves him with guard duty. Lynx-O and Cheetarah run reconnaissance to find out if Mumm-Ra is truly back or not.
Catfight Chris Trengove September 22, 1986 76 76
By disguising himself as Jaga, Mumm-Ra tricks Lion-O into believing the new ThunderCats are traitors so that they will fight amongst themselves.
Psych Out Sandy Fries September 23, 1986 77 77
Mumm-Ra tells Alluro where to find a talisman that boosts the self-confidence of the one who possesses it so that they become nearly invincible. And Snarf learns that true courage comes from within.
The Mask of Gorgon Romeo Muller September 24, 1986 78 78
Ma-Mutt digs up an ancient book which leads Mumm-Ra to search for the ancient evil of the mask of Gorgon.
The Mad Bubbler Kimberly Morris September 25, 1986 79 79
The Lunatacs look for Thundrylium[7] in a cave on Hook mountain only to be driven mad by a strange creature who turns them against each other.
Together We Stand Herb Engelhardt September 26, 1986 80 80
Mumm-Ra coats the Bezerker's weapons and armor with Thundranium[10] and Wilykit and Wilykat find that guarding Cats Lair isn't always a breeze.
Ravage Island George Hampton and Mike Moore September 29, 1986 81 81
Mumm-Ra activates a mesmerising beacon on Ravage Island which draws the ThunderCats to it and takes hold of their minds.
Time Switch Sandy Fries September 30, 1986 82 82
While taking care of a dangerous Suspension Capsule,[9] dug up near Cats Lair, Lion-O is exposed to harmful gasses inside which cause him grow younger. If the Thundercats don't find a solution in time, he will rapidly become younger until non-existent.
The Sound Stones J. Larry Carroll October 1, 1986 83 83
Vultureman builds a sonic gun from a sound stone he stole in Dark Side as the Lunatacs join with him to attack the Tower of Omens.
Day of the Eclipse Kimberly Morris October 2, 1986 84 84
The day of the centennial total eclipse has arrived and any spell Mumm-Ra casts will last until the next eclipse. He declares a "Day of Decay" on the Cats Lair causing it to fall apart.
Sideswipe William Overgard October 3, 1986 85 85
Chilla freezes Snarfer's spaceship as he heads back to the Tower of Omens with Berbil Mexican Takeout. When Mandora gets involved, Chilla freezes her and becomes a fugitive from the law as Mandora sets her sights on bringing her in.
Mumm-Rana's Belt James Rose October 6, 1986 86 86
Luna discovers that her grandmother's magic belt is now in the possession of Mumm-Rana who claimed it after battle. She heads straight for the white pyramid with Pumyra hot on her tail.
Hachiman's Honor J. Larry Carroll October 7, 1986 87 87
While Hachiman is on his way to the Tower of Omens, Luna steals his sword the ThunderCutter and gives it to an automaton. Lion-O and the ThunderKittens head out to find their old friend.
Runaways Bill Ratter October 8, 1986 88 88
Fed up of feeling useless Wilykat convinces his twin to run away from home, but living on their own is more dangerous than they realized. The other ThunderCats search desperately to find them as they all must learn a lesson in communication.
Hair of the Dog Chris Trengove October 9, 1986 89 89
While all the ThunderCats except Lion-O are gone, Mumm-Ra switches Ma-Mutt with Snarf. Ma-Mutt poisons Lion-O allowing Mumm-Ra to move in.
Vultureman's Revenge Herb Engelhardt October 10, 1986 90 90
Vultureman builds a Thundranium[10] projector which is capable of creating concentrated regions of Thundranium. When the ThunderKittens damage it, he damages their spaceboard sending them off into danger and while Lion-O and Snarf search desperately for the kids, Vultureman plans his revenge.

Season 3 (1988)

Title Writer Original airdate Production code #
ThunderCubs Part I Peter Lawrence 91 91
Mumm-Ra learns of the treasure of Thundera[12] and the Sword of Plun-darr which destroyed Thundera. He recreates Thundera and travels there whilst the ThunderCats try to find him.
ThunderCubs Part II Peter Lawrence 92 92
After being rescued the ThunderKittens give a presentation on their observations of New Thundera. Vultureman renovates the Rat Star to ambush the ThunderCats on their way to New Thundera.
ThunderCubs Part III Peter Lawrence 93 93
Mumm-Ra claims the Sword of Plun-darr and nears the treasure of Thundera. The ThunderCats land on New Thundera.
ThunderCubs Part IV Peter Lawrence 94 94
The Mutants arrive and Mumm-Ra has them hide a decoy Book of Omens[13] leading the ThunderCats in the wrong direction.
ThunderCubs Part V Peter Lawrence 95 95
The ThunderCubs[14] return to Third Earth and join with the ThunderKittens to mount a rescue mission which will infiltrate Sky Tomb whilst Lion-O continues to battle Mumm-Ra.
Totem of Dera J. Larry Carroll 96 96
Mumm-Ra recovers the Totem of Dera[12] and learns of its healing powers which can be used to bring inanimate objects to life. He sends the Mutants out to use it against the ThunderCats.
Chain of Loyalty Bill Ratter and Peter Lawrence 97 97
Whilst studying the Book of Omens[13] Lion-O learns of the Chain of Loyalty[12] and Jaga instructs him to recover it from New Thundera. But when Mumm-Ra breaks the chain, the Thundercats turn against each other and Lion-O must find a way to stop them from destroying each other.
Crystal Canyon Sandy Fries 98 98
Tygra finds a powerful stone which slowly takes control of his mind. He refuses to listen as Lion-O tries to warn him that the stone is dangerous.
The Telepathy Beam Kimberly Morris 99 99
Vultureman uses a new weapon on Cheetara to overwhelm her sixth sense in an attempt to destroy her confidence and distract her from sensing the truth that Panthro has become a prisoner and turned slave to upgrade Sky Tomb to be able to make a trip to New Thundera.
Exile Isle William Overgard 100 100
The Thundercats capture the Lunatacs, put them on trial, and exile them to a desolate planet. However, there is another old enemy of the Thundercats trapped on Exile Isle, with whom the Lunatacs soon team up to plan a destructive return to Third Earth.
Key to Thundera Matthew Malach 101 101
During an attempt to decode the Book of Omens, Lion-O accidentally traps himself within its pages, prompting Mumm-Ra to try to steal the book from Cats' Lair. Meanwhile, Panthro discovers a mysterious key on New Thundera.
Return of the ThunderCubs J. Larry Carroll 102 102
Tygra, Cheetara and Panthro fall under Mumm-Ra's power on New Thundera, and he tries to use Cheetara's Sixth Sense to locate the Treasure of Thundera. To rescue his friends, Lion-O must convince the mutants to fly him from Third Earth in the Ratstar.
The Formula Kimberly Morris 103 103
Alluro's new superfuel formula for Sky Tomb unexpectedly seems to boost the growth of local plant and animal life to massive proportions. Luna orders the mutants to spray it around Cats' Lair, leaving the Thundercats trapped in a gigantic savage garden.
Locket of Lies Bill Ratter 104 104
Mumm-Ra creates an evil trinket which the Thundercats mistake for a piece of the Treasure of Thundera. It soon leads them into deep trouble on New Thundera, and nobody is around to rescue them.
Bracelet of Power Bill Ratter 105 105
The Feliner returns from New Thundera with a mysterious bracelet. When Snarf puts it on, he discovers it has the power to turn Thundercats into his obedient servants. While he toys with this new power, Mumm-Ra plots to steal the bracelet for his own evil purposes.
The Wild Workout Becky Hartman 106 106
The Lunatacs hook up exercise machines to generate power for Sky Tomb's engines, but their own laziness forces them to find Thundercats to do the hard work. Meanwhile, Mumm-Ra plans to lure the Thundercats into a freezing trap in the Caverns of Cold on New Thundera.
The Thunderscope George Hampton and Mike Moore 107 107
Lion-O and Snarf recover a mysterious telescope from the wreckage of their original spaceship. Mumm-Ra recognizes it as the Thunderscope, which allows its user to locate pieces of the Treasure of Thundera. Lion-O must discover its purpose and keep it out of Mumm-Ra's evil hands.
The Jade Dragon William Overgard 108 108
Mumm-Ra discovers the power of one of the pieces of the treasure of Thundera. The Double-Headed Dragon of Doom, or the Jade Dragon possess the power to entrap people in its stomach. The legend says that Haji-Man's ancestor gave the dragon to his wife as a marriage gift, and since her father was so against their marriage, he put a curse on the dragon and it engulfed Haji-man's ancestor. Jaga freed the him, and he gave the dragon to Jaga for safe keeping. Now, the Thundercats have found the Jade Dragon, and Mumm-Ra manages to trap Lion-O and Cheetara in it. Haji-man is their only hope.
The Circus Train William Overgard 109 109
A bounty hunter known as Captain Bragg comes to Third Earth to help the Thundercats get rid of the Mutants and the Lunatacks. Capt Bragg tricks Wilykat in going with him and they first go after the Mutants. After capturing them, they go to capture the Lunataks. They capture all except Luna and Amuk, who free the other Lunataks, put Bragg in a cage and tie Wilykat to the train's engine.
The Last Day J. Larry Carroll 110 110
Impatient with Mumm-Ra failing them time and time again, the Ancient Spirits of Evil give him one final chance: destroy the Thundercats within twenty-four hours, or face exile. To this end, he is granted extraordinary power by the Spirits, and grows to a gigantic size.

Season 4 (1989)

Title Writer Original airdate Production code #
Return to Thundera Part I Peter Lawrence 111 111
The Ancient Spirits of Evil give new life to Mumm-Ra and Ma-Mutt, send them to New Thundera, and build a new Pyramid for Mumm-Ra. The Thundercats say goodbye to Third Earth and depart for Thundera, leaving Tygra and Pumyra behind to watch Cat's Lair and the Tower of Omens. The Thundercats soon arrive and begin plans to build a new lair. Mumm-Ra meanwhile learns that the planet's gravity is controlled by the Gyroscope under the Churning Rocks at the center of the planet and will use this knowledge to destroy the Thundercats and trick the Gyroscope's guardian, the ancient sorceress Jaguara.
Return to Thundera Part II Peter Lawrence 112 112
More and more earthquakes are occurring because of the malfunctioning Gyroscope. Meanwhile Lion-O receives a distress signal from Thunderian refugees, and he, Cheetara, and Snarf go to find them. Mumm-Ra resurrects Grune the Destroyer, and Grune seeks out Lion-O and Cheetara. Grune finds and fights them, breaks the Sword of Omens, and then he chains them up on the Churning Rocks. Snarf, who was hiding, gathers the pieces of the Sword to take back to Bengali to be fixed. Snarf gets captured by Char, a thief who wants the Sword for himself.
Return to Thundera Part III Peter Lawrence 113 113
Lion-O, Panthro, and the Thunderkittens take the Whisker, a new flying vehicle, to the Churning Rocks to rescue the Thunderian refugees who had called from there. The Thundercats get captured by Two-Time, a robot with 2 heads. Two-Time takes them aboard his spaceship, Dome-Down, and the Thundercats see that he has also captured the refugees. Lion-O defeats Two-Time and the refugees are freed. Meanwhile, Lynx-O, Cheetara, and Bengali spot Mumm-Ra near the Churning Rocks, and inform Lion-O of this. Lion-O, Panthro, and the Thundekittens head to the Churning Rocks and confront Mumm-Ra, who is in the form of Jaga again.
Return to Thundera Part IV Peter Lawrence 114 114
Mumm-Ra sends Ma-Mutt disguised as Mandora to free the Mutants from Capt. Bragg's circus train and sends Bragg and Crowman falling into deep space. The Mutants are then ordered by Mumm-Ra to get rid of Tygra and Pumyra. The Mutants attack Snowman on Hook Mt. and Snowmeyow gets Pumyra for help and Tygra contacts the real Mandora to save Bragg and Crowman. Then together, they recapture the Mutants. Meanwhile on New Thundera, the earthquake tremors grow worse and the new Cats Lair collapses trapping Snarf in the ruins. Lion-O uses the sword to contact the other Thundercats and they rush to the Lair to save Snarf.
Return to Thundera Part V Peter Lawrence 115 115
After another earthquake caused by Mumm-Ra ruins the new Cats Lair construction site, the Thundercats go to see Jaguara and confront Mumm-Ra. Unfortunately, Mumm-Ra puts up a force field over entrance. Jaga appears to Lion-O and tells him to use the Eye of Thundera to get to Jaguara and the Gyroscope. Lion-O does so and battles Mumm-Ra, who throws him into the bottomless pit underneath the Gyroscope. Lion-O however, manages to throw his grappling hook to the top, which pulls him back up. Lion-O then shines the signal, which goes through the force field. All the Thundercats leap through the signal which takes them through the force field. Together, they fire all their weapons at Mumm-Ra and he is defeated. But before he leaves, he breaks the cord that holds the Gyroscope above the pit and it falls through. Now, New Thundera is literally falling apart.
Leah J. Larry Carroll and David Carren 116 116
The Ancient Spirits of Evil bring the Mirror Wraith to Mumm-Ra, and he disguises it as a child's toy. Mumm-Ra then intercepts a thunderian escape pod which carries in it a little girl. He gives the toy to the child (Leah), and leaves. She is rescued by the Thundercats, and goes into New Cat's Lair with the doll.
Frogman Kimberly Morris 117 117
Wily Kit and Kat are constructing a well for the New Cat's Lair on New Thundera. The Thundercats on New Thundera receive a distress signal from Thunderian refugees trying to find their way to New Thundera. The Kittens are left alone with Snarf on at the New Cat's Lair, and Lion-O and Snarfer are out constructing an early warning device (I guess for weather purposes). The rest of the Thundercats seek out the refugees in space. When Wily Kit and Kat strike water, they accidentally unleash a monster that Jaga trapped in the underground lake centuries ago.
The Heritage Bill Ratter and Peter Lawrence 118 118
Wily Kit and Kat, exploring New Thundera, stumble upon an Orb of Gold, and pick it up thinking that it is a part of their Heritage. Possessed by the power of the Golden Sphere of City, the ThunderKittens get greedy, and let the power of the orb overcome them. Mumm-Ra manages to get a hold of the orb, and his powers get four times more powerful.
Screwloose William Overgard 119 119
Jaguara cannot work New Thundera's Gyro on her own. The Thundercats order a robot to aid her in running the Gyro. Screw Loose, a robot who specializes in Gyro's, comes to New Thundera. Mumm-Ra manages to mess up Screw Loose's brain so he becomes destructive instead of helpful. The Thundercats must help Jagara get Screw Loose under control, before the entire planet is destroyed.
Malcar George Hampton and Mike Moore 120 120
Mumm-Ra summons Malcar, an ancient alchemist, to return from the dead. The alchemist returns old and weak, and Mumm-Ra must restore his youth and power. Malcar regains his powers to use them against the Thundercats.
Helpless Laughter Matthew Malach 121 121
A convergence of the Moons of Plun-Darr causes a drought on Thundera. Panthro and Snarf go looking for water, then Ezuka, the flying Serpent of Dreary Canal wanting to get water itself, attacks Panthro and Snarf and causes them to fall into the Swamp of the Laughing Lilypads, making them laugh out of control. Ezuka attacks the Lair, still looking for water. Lion-O uses the Sword to make some rain, then he and Ben-Gali use the Thunderstrike to melt some ice, but Mumm-Ra comes along and causes a flood.
Cracker's Revenge William Overgard 122 122
Capt. Cracker and his mechanical parrot Polly land on Way-Out Back and free the Lunatacs and put Bragg and Crownan in one of the train's cages. They plan to go to Third Earth to attack it since most of the Thundercats are no longer on Third Earth. Meanwhile the ThunderCats have learned Cracker escaped and Snarfer and Mandora go to catch him. Bragg has Crownan ride a fire exstiquisher, so he can get into space and get help. Mandora finds him, and the three of them go to Third Earth. Mandora fights with Cracker and the Lunatacs, but is beaten and she and Snarfer are tied to her cycle and sent towards a mountain. Lion-O, Panthro, and Cheetara arrive and Lion-O saves Mandora and the others. Meanwhile Cracker and the Lunatacs go to attack Cats Lair.
The Mossland Monster Chris Trengove 123 123
Tygra, on a solo trip to New Thundera to meet the other Thundercats, decides to take a shortcut through a meteor shower. His ship is damaged, and he lands on an unexplored region of New Thundera. The Moss-Land. It turns out that the moss in moss-land is part of a giant monster who captures Tygra with its moss. Lion-O and Panthro set out to save Tygra and battle the Moss Monster.
Ma-Mutt's Confusion Beth Bornstein 124 124
Mumm-Ra has a new device, the Babylonian Barbarian Boiler, that he plans to use on Cats Lair. Ma-Mutt fools around too much and Mumm-Ra banishes him from the Pyramid. Later, the Thunderkittens, Snarf, and Snarfer bring Ma-Mutt back to Cats Lair and then Mumm-Ra fires the Boiler's beam at the Lair, which causes it to start melting. Snarfer makes a communicating device (because Ma-Mutt was trying to tell them about the beam), so they can understand Ma-Mutt. Ma-Mutt starts telling them of the Boiler, but Mumm-Ra sees this and through the Cauldron's magic brings Ma-Mutt back to the Pyramid.
Shadowmaster Dennis J. Woodyard 125 125
From the Shadow Realm, the Shadowmaster contacts the Ancient Spirits of Evil (ASOE), telling them of how he captured Lion-O's father, Claudus, just before Thundera blew up. Then the Shadowmaster, through a bad dream, shows Lion-O his captured father and challenges Lion-O to a fight. Lion-O goes to the Shadow Realm through the Book and Sword of Omens, and is able to fight the Shadowmaster as long as the Sword stays bonded to the book. However, the Shadowmaster sends a huge bat to steal the Sword. It succeeds, and then Lion-O becomes very weak in the Shadow Realm. Mumm-Ra meanwhile, feeling like the ASOE will turn against him in favor of the Shadowmaster, sends Ma-Mutt to secretly steal the sword from the bat and put it back near the book. This will be crucial to Lion-O's triumph in this realm.
Swan Song William Overgard 126 126
An Ecology Inspector (EI) comes to Thundera to inspect the new Cats Lair. His ship uses the SWAN system (Space Way Airborn Navigations) to direct him to planets all over the universe. When he arrives on Thundera, he gets ambushed by Two-Time (see Return to Thundera, Part III, this page). Two-Time uses a hologram to make the EI's ship crash into a mountain, and then when the Thundercats come to rescue the EI in the Feliner, Two-Time uses the hologram again. Lion-O manages to fly around the mountain and lands the Feliner. Meanwhile, Two-Time flies to new Cats Lair in his spaceship, Dome-Down. He actually picks up the whole Lair and keeps it inside Dome-Down.
Touch of Amortus Bill Ratter 127 127
Mumm-Ra orders Amortus, a being he banished to the Land of No Return centuries ago, to destroy Lynx-O. Amortus makes Lynx-O crash in the Thunderstrike, and then he touches Lynx-O's face. The spell from the touch makes Lynx-O feel like he is an outcast, so he leaves to join Amortus in the Land of No Return. The other TCats, Lion-O, Panthro, and Cheetara, go after him. In the Land of No Return, Amortus again touches Lynx-O, this time causing him to turn to stone. The other TCats arrive and try to beat Amortus, but he touches all of them, causing them to start turning to stone. But just as Lion-O is about to turn entirely to stone, he calls the Sword and it breaks them free.
The Zaxx Factor Matthew Malach 128 128
Vultureman escapes from exile by hijacking a bookmobile. He finds a disk containing ancient history about two powerful evil forces on Third Earth: Mumm-Ra and his enemy Zaxx. Using this information, Vultureman plots to defeat Mumm-Ra and rule the universe.
Well of Doubt Dennis J. Woodyard 129 129
The Thundercats use a new Tower signal to guide a Thunderian ship in; aboard are Baron Tass and Mr. Grubber, a devious pair of Thunderians. Later Lion-O sends Torr, Baron Tass and Mr. Grubber to get water, but on the way the Baron stops at the Well of Doubt and gets some of its water. The water causes a person to become very doubtful of his own abilities. When they get back to the Thundercats, Baron Tass gives some of the water to Lion-O. On the way to inspecting the new Tower in the Whisker, Lion-O feels the effects of the water and causes the Whisker to crash. Tass comes back (from getting his Guardsman, giant stone-men), and has them attack the Thundercats. Will Lion-O recover his courage and determination?
The Book of Omens William Overgard 130 130
Finally Panthr-O deciphers how to use the Key of Omens. He enters the code to open the lock and, suddenly, the Guardian of Omens is summoned and it tells the Thundercats they have 24 hours to present both the key and present four other items to the four places in disgrace (geological disasters) all over New Thundera. All was proceeding correctly except for the key, which was stolen by the evil Mumm-Ra. However, he enters the Book just when Lion-O found him and the battle will go on inside the book. This presented a somewhat legitimate finale for the complete series, with an open ending (which will continue in a short series of comics in an "after future" saga on the year 2002).


  1. Sword of Omens - A mystic sword originally carried by Jaga which he then passed on to Lion-O shortly before his death.
  2. Eye of Thundera - The source of the Thundercats power, it is embedded in the Sword of Omens. It awakens when summoned by Lion-O and appears as a black cat head against a red background.
  3. 3.0 3.1 3.2 Ro-Bear Berbils - a race of small robotic bears who grow fruit.
  4. Trolligs - a race of smaller troll-like creatures who frequently raid the Berbil village to steal their fruit.
  5. Giantorrs - a race of giants who live on top of the Trolligs mountain where the trollberry bushes grow. They refuse to let the Trolligs eat the leaves off those bushes unless they bring them Ro-Bear Berbil fruit. After the ThunderCats drive the Trolligs and Giantorrs off, the Berbils become their allies and offer to help them build their new home.
  6. Cats Lair - The name of the ThunderCats kick ass home and fortress on Third Earth, a replica of the one on Thundera, it was designed by Tygra and built quickly with the help of the Berbils.
  7. 7.0 7.1 7.2 7.3 Thundrylium - a mineral that occurs on Third Earth, Thundera and other planets that the ThunderCats and Lunataks alike use for fuel.
  8. Bulkans - a race of anthropomorphic sheep, they are poor and curious.
  9. 9.0 9.1 Suspension Capsule - stasis pods which the Thundercats used on their journey from Thundera to Third Earth so they would not age.
  10. 10.0 10.1 10.2 10.3 10.4 Thundranium (known as fire rocks on Third Earth) - a mineral that weakens Thunderians, and can eventually kill them. (Analogous to Superman and Green Kryptonite)
  11. Dark Side - Forbidden territory to ThunderCats and Mutants alike because of the danger there. When the Lunatacs came to Third Earth years earlier and tried to destroy Mumm-Ra, he imprisoned them there.
  12. 12.0 12.1 12.2 Treasure of Thundera/ThunderCats - A collection of magic objects with various powers, the most important being the Book of Omens.
  13. 13.0 13.1 Book of Omens - This book contains the secrets of the ThunderCats
  14. In the previous episode Cheetara, Tygra, Panthro, Snarf, and Snarfer all became younger after being tricked into entering the valley of youth.


External links


Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.