The BEST Episodes of ThunderCats

Every episode ever - ranked by fan votes!

Last Updated: Oct 4, 2019

Network: Syndicated

The inhabitants of the planet Thundera evacuate just before it is destroyed. They were pursued by a band of mutants. All but one of their escape ships was destroyed. Only a small group of Thunderans (Thundercats) remained. With only half engine power, the group, which was led by Jaga, had to set a course for the nearest planet. Jaga commanded their ship while the other seven were in their stasis tubes. Jaga died on their journey to Third Earth and their ship crashed there. Soon they made friends with various groups in the area and they designed a fortress. Mumm-Ra the centuries-old embodiment of evil, along with the mutants that destroyed the rest of the Thunderans are a constant threat. But Lion-O, the new leader of the Thundercats, with his weapon the "Sword of Omens" will help the Thundercats to have a standing chance.

Return of the ThunderCubs

#1 - Return of the ThunderCubs

Season 3 - Episode 12

Panthro, Tygra, and Cheetara return to New Thundera in the Feliner to find more of the Treasure of Thundera, but Mumm-Ra shoots the Feliner down and, as the Fog of Despair, sends them to the Canyons of Youth, which changes them back into Thundercubs. Then Mumm-Ra disguises himself as Lion-O and tells the Thundercubs to find the treasure for him. Meanwhile, back on Third Earth, Lion-O and Snarf decide to go rescue the Thundercats on New Thundera, but they must ask the Mutants to take them to New Thundera in the Rat-Star. The Mutants agree, secretly planning to attack Lion-O once they're in space. They do attack and imprison him and Snarf on the way to Thundera, but they manage to break out. Cheetara meanwhile, using her sixth sense, locates part of the treasure, the Mirror of Truth. The real Lion-O shows up, and uses the Sword of Omens with the Mirror of Truth to restore the cubs to their proper age, and Mumm-Ra reveals himself and turns into Mumm-Ra the everliving. Cheetara uses the mi

star 8.38
21 votes
Key to Thundera

#2 - Key to Thundera

Season 3 - Episode 11

While trying to figure out a way to read the Book of Omens, Lion-O tries looking through the sword at the book. He is immediately drawn into the book, where a voice asks him if he has ""the key."" Lion-O says he doesn't, and four dragon heads appear and shoot fire at him. Snarf, who saw Lion-O get sucked into the book, tries to show Cheetara what happened, and he too gets sucked in. Mumm-Ra, who also watched Lion-O get sucked in, goes to cats lair and takes the book so he can destroy it with Lion-O inside. Meanwhile, just by coincidence, Panthro finds an odd looking key on Thundera. He and Tygra head back to Third Earth with the key, not knowing what it's for. Back on Third Earth, Mumm-Ra is just about to boil the book when Lion-O calls for the sword, and it brings him and Snarf back outside. Mumm-Ra takes the sword and looks through it at the book, and he gets sucked in! But Lion-O has to save him because of the code of Thundera, and Lion-O does save him. Panthro and Tygra arrive with t

star 8.30
20 votes
Return to Thundera (5)

#3 - Return to Thundera (5)

Season 4 - Episode 5

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. But Lion-O throws the sword in the spot where the Gyroscope used to be and calls upon the Thundercat Ancestors for help. The sword starts

star 8.11
19 votes
Well of Doubt

#4 - Well of Doubt

Season 4 - Episode 19

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. Jagara has the others hold the Sword, and when Lion-O grabs hold of the sword, he's free of the water's effect. Then he fights off the Guardsman, and makes a storm, which causes the Guardsman to fall apart, and Tass promises to change his ways.

star 8.07
14 votes
Out of Sight

#5 - Out of Sight

Season 1 - Episode 57

Willa is captured by the Mutants, and Tygra and Nayda, Willa's sister, must go to Castle Plun-darr to save her. Tygra uses the invisibilty power of his whip on both of them, so they could sneak into the castle and rescue Willa, but having 2 people at a time takes too much power from the whip, so they are stuck being invisible. Lion-o uses the Sword to make them visible once again and Willa is rescued.

star 8.07
15 votes
The Wild Workout

#6 - The Wild Workout

Season 3 - Episode 16

Lion-O, Panthro, and Snarf set out to look for more pieces of the Treasure of Thundera, and Mumm-Ra sets a trap for them. He freezes them in the caverns of cold on Thundera. Meanwhile, back on third earth, the Luna-tacs, in need of another source of power for their ship, use exercise machines to power it up. They capture the other Thundercats and force them to workout on the machines to power up the ship. The Thundercats manage to overwork the power supply, and escape from Sky Tomb. Back in the caverns, Snarf manages to get the sword of omens to Lion-O with his tail, and they escape and return to third earth.

star 8.06
17 votes
The Zaxx Factor

#7 - The Zaxx Factor

Season 4 - Episode 18

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. Zaxx used a Rosencrest medallion, but Zaxx was defeated when Mumm-Ra stole the medalion trapping Zaxx in it. Vultureman plots to get the medalion, defeat Mumm-Ra, and rule the universe. So Zaxx uses Vultureman to find and defeat Mumm-Ra. But there's a terrible ""side effect"" to the medalion, anyone who wears it loses his own life and BECOMES Zaxx. When Vultureman learns of this, he changes his mind. The Thundercats get caught in this situation when Vultureman attacks Panthro and Snarf and after they crash, Snarf dissappears. Zaxx then uses Snarf to attack Mumm-Ra and Zaxx takes over Snarf's body. The other Thundercats arrive and save Snarf. Mumm-Ra defeats Zaxx once more by takin the medalion, but the pyramid also collapses on Mumm-Ra.

star 8.05
19 votes
The Trouble with ThunderKittens

#8 - The Trouble with ThunderKittens

Season 1 - Episode 62

The Thunderkittens steal the Thundercats' weapons so they can prove they can use them, but the Mutants steal the weapons! Lion-O and the kittens must get the weapons back from the Mutants.

star 8.05
19 votes
Fond Memories

#9 - Fond Memories

Season 1 - Episode 65

Mumm-Ra pretending to be one of the ThunderCats friends takes Lion-O to a gallery of the ThunderCats accomplishments. However, the pictures can come to life and Lion-O must battle Rataro, Safari Joe, and others. ONce the other ThunderCats arrive they end up in trouble and Lion-O is confronted by Mumm-Ra who has made himself into a carbon copy of Lion-O. It's Lion-O VS Lion-O and is a draw, until Lion-O shows Mumm-Ra his reflection.

star 8.04
24 votes
The Book of Omens

#10 - The Book of Omens

Season 4 - Episode 20

New Thundera is being torn apart and the Thundercats must present certain artifacts at various dangerous locations that used to be beautiful places, then Lion-O must go into the book and give the Key of Thundera to the guardian of the book ""at the 24th hour,"" or the Thundercats will be frozen in time and New Thundera will be destroyed. But Mumm-Ra steals the book and key and journeys into the book himself. He wants to save New Thundera BUT wants the Thundercats frozen in time. The Ancient Spirits of Evil try to stop Mumm-Ra because they fear if Mumm-Ra goes into the book, their powers will cease to exist. The other Thundercats run into problems also at the locations they are supposed to be at. Lion-O goes into the book using the Sword of Omens and battles Mumm-Ra one on one, neither of them using any magic. Even when Mumm-Ra cheats, Lion-O still wins. The ASOE summon their ""champion,"" Pyron, to then fight Lion-O, but Lion-O gets the dragons in the book to fry him... He presents the key

star 8.04
26 votes
Return to Thundera (4)

#11 - Return to Thundera (4)

Season 4 - Episode 4

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. Afterwards, Mumm-Ra destroys the Gyroscope's regulator...

star 8.00
18 votes
Turmagar the Tuska

#12 - Turmagar the Tuska

Season 1 - Episode 45

An evil robot monster is attacking the Tuska Village, in an area unexplored by the Thundercats. Turmagar, the leader of the Tuskas, travels to the Cat's Lair to ask for aid in defeating the Techno-Pede robot which is destroying his village. The Thundercats agree to help Turmagar, and set out to the Tuska Village.

star 8.00
17 votes
Time Switch

#13 - Time Switch

Season 2 - Episode 12

While burying one of the time capsules that transported the Thundercats to Third Earth, it smashes apart and Lion-O gets caught in its gases, making him younger and younger by the minute. The other Thundercats must find a way to reverse the process and realize the Cave of Time is the only way, but they must get Lion-O there before he "vanishes" from existence. Things get worse when the young Lion-O and Snarf are captured by the Lunataks.

star 8.00
17 votes
ThunderCubs (1)

#14 - ThunderCubs (1)

Season 3 - Episode 1

Mumm-Ra learns about the Treasure of Thundera and the Sword of Plundarr (Jaga had beaten Ratilla, who owned the Sword, and then buried the sword deep underground), and he and Ma-Mutt ""travel back in time and space"" to explore the debris of Thundera and look for the sword, which causes the planet to reform. The Thundercats find out about this and must make the journey to New Thundera to stop Mumm-Ra. Lynx-O and the Thunderkittens are left at the tower while the other Thundercats at the Lair are preparing the Feliner for the trip to New Thundera. Vultureman notices that the tower is only guarded by 3 Thundercats and goes to Sky Tomb and tells Luna. Luna then sends Red Eye and Tug Mug to attack the Tower, and they capture Lynx-O and the Thunderkittens.

star 8.00
21 votes
The Circus Train

#15 - The Circus Train

Season 3 - Episode 19

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. Lion-O and Wilykit arrive to save Wilykat and the Lunataks are defeated. All the Mutants and all the Lunataks are captured and exiled.

star 8.00
17 votes
Lion-O's Anointment Third Day: Trial of Cunning

#16 - Lion-O's Anointment Third Day: Trial of Cunning

Season 1 - Episode 46

Wily Kit and Kat stand in Lion-O's way on the third day of his trials. Lion-O must beat them through the maze of infinity. Attempting to stop Lion-O and slow him down, the kids set traps in the maze. He manages however to avoid their traps. In order to beat them through the maze, Lion-O plays their own tricks on them, and tricks them into losing the race through the maze.

star 7.96
25 votes
Feliner (2)

#17 - Feliner (2)

Season 1 - Episode 30

Vultureman summons Ratar-O to take him to the planet of the Snarfs to capture one of them and use it as ransom with the Thundercats. Snarf, thinking his entire race was wiped out when Thundera blew up, finds out that they have captured Snarfer, his little nephew. The Thundercats set out to find the Mutants and save Snarfer. After successfully saving Snarfer, the Thundercats are faced with the problem of returning Snarfer to his planet. Panthro cleverly invents the Feliner, a spaceship. In order for it to work, though, the machine need a hyperspace mega-condenser. Snarf reminds him that there is one on Ratar-O's Ratstar. The Thundercats once again pursue the Mutants to the wreckage site of the Ratstar to take their mega-condenser.

star 7.95
22 votes
Mumm-Ra Lives (4)

#18 - Mumm-Ra Lives (4)

Season 2 - Episode 4

Young Snarfer, Snarfs nephew, arives on third earth. His ship has gone off course though and landed in territory of the Luna-tacks. The Luna-tacks manage to capture Snarfer, and the Thundercats must venture into Darkside to save young Snarfer so he can work the Tower of Omens.

star 7.95
20 votes
Pumm-Ra

#19 - Pumm-Ra

Season 1 - Episode 5

Mumm-Ra uses his shapeshifting abilities to pass himself off as a Thunderian so he can stage the "rescue" of Cheetara and infiltrate Cats' Lair.

star 7.95
92 votes
Crystal Canyon

#20 - Crystal Canyon

Season 3 - Episode 8

Lion-O, Lynx-O, Snarf and Tygra go to the Crystal Canyon, thinking the Lunataks somehow got the Treasure of Thundera. While there, they encounter Aluro and Chilla. The two Lunataks trick the Thundercats by confusing them using with their reflections. They knock out the Thunderstrike and cause it to crash. Lynx-O is seriously injured and Lion-O is knocked unconscious. Tygra and Snarf find the Keystone and when Tygra holds the Keystone, he becomes convinced that it is making him more powerful. He uses it to restore the Thunderstrike, and heal Lion-O and Lynx-O. They return to the Lair and the other 3 Thundercats learn Tygra has become seriously addicted to the Keystone. When they try to tell Tygra he's become a slave to the Keystone, he doesn't believe them. Later in a battle against Aluro, Tygra thinks he's invincible, but Aluro proves him wrong and takes the Keystone from Tygra. Then Aluro himself becomes addicted to the Keystone. Aluro captures Lion-O and Lynx-O forcing them to come w

star 7.94
18 votes
Touch of Amortus

#21 - Touch of Amortus

Season 4 - Episode 17

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. It also releases other warriors trapped by Amortus, and they all come and defeat him. Lynx-O is rescued just in time- just before the stone is permanent- and they all go home

star 7.94
17 votes
Hachiman's Honor

#22 - Hachiman's Honor

Season 2 - Episode 17

Hatchiman rescues an old woman not knowing it's Luna. She "invites" him to her "cave" and there she and Chilla and Aluro attack him and take his sword, the Thundercutter. The Thunderkittens find Hatchiman and rescue him. The Lunataks plan to use the Thundercutter with their new samurai robot, Automaton, to fight Lion-O and the Sword of Omens. The Thundercutter can't tell who's good and who's evil in the fight but when Hatchiman touches the sword, the Thundercutter destroys the robot.

star 7.94
16 votes
Exodus

#23 - Exodus

Season 1 - Episode 1

With their home planet, Thundera, about to explode, the Thunderians flee to a distant galaxy. Before they can make the long journey the Mutants sweep in and destroy most of the fleet in an attempt to capture the Eye of Thundera. Due to the attack, the Thundercats find themselves on a distant planet. A grown-up Lion-O must save his Thundercats from the Mutants on Third Earth.

star 7.94
362 votes
The Mumm-Ra Berbil

#24 - The Mumm-Ra Berbil

Season 1 - Episode 47

Mumm-ra transforms himself into a ro-bear berbil (a Thundercat ally). He acts hurt and the Thundercats let him stay at Cats Lair. One night, Mumm-ra(the berbil) puts all the Thundercats under his spell, except Snarf, because Tygra held off Mumm-ra just long enough for Snarf to escape. Lion-O was sleeping out in the woods, and Snarf ran to him and told him what happened. Lion-O came back and fought Mumm-ra, who was actually beating Lion-O. Mumm-ra was wearing special glasses so he couldn't see his reflection. Eventually, Lion-O used the Thundercat signal, broke Mumm-ra's spell and his glasses, and finally defeated him with his reflection.

star 7.93
15 votes
Lion-O's Anointment First Day: Trial of Strength

#25 - Lion-O's Anointment First Day: Trial of Strength

Season 1 - Episode 37

On Lion-O's 20th birthday, he must pass a set of trials to become the true Lord of the ThunderCats. Even though he is the hereditary Lord of the ThunderCats, he must prove himself to be worthy of that title. His first test is to beat Panthro in a duel to test his strength.

star 7.92
26 votes