ThunderCats (or CosmoCats in some countries) was an American science fiction TV series which debuted in 1985. It featured anthopomorphic animals who greatly resemble humans. In 1986, a TV movie titled ThunderCats-HO! was released, after which came the second season, which aired from 1986 to 1987, the third season, which aired from 1987 to 1988, the fourth season, which aired from 1988 to 1989, and finally, the fifth season, which aired from 1989 to 1990. In 1985, a comic series based on ThunderCats was released.
On June 5, 2007, it was announced that Warner Brothers was making a CGI-animated feature film based on ThunderCats, but the project was canned. Instead, the original's creators decided to make a new animated show, and make it a reboot of the original. On July 29, 2011, a 1-hour double pilot episode was aired on Cartoon Network. The fans' reaction had been mostly very positive. As of now, each new episode airs on Fridays.
The 1985 series focuses on the ThunderCats, six humanoids who are based on felines and come from the planet Thundera. Their home planet was destroyed, so they fled to a planet called Third Earth. Their arch-nemesis is an undead mummy called Mumm-Ra.
ThunderCats was a succesful TV series, and as a result, spawned a comic book series by Marvel Comics, which was published from December 1985 to 1988. In 1988, a new ThunderCats comic series was published by Marvel UK. In 2002, another ThunderCats comic series was published by DC Comics. There was also a crossover between ThunderCats and Battle of the Planets.
Random House produced around a dozen Thundercats books between 1985 and 1987 intended for very young readers that might not be old enough to read the comics. Most of these were original stories set in the Thundercats universe. Almost all of these were illustrated books intended for beginners readers. There was also a coloring book: Mumm Ra Meets His Match, a Story to Color. Two choose your own adventure books for young adults were produced by Random House in 1985: Find Your Fantasy #3: Thundercats and the Ghost Warrior and Find Your Fantasy #4: Thundercats and the Snowmen of Hook Mountain.
 Video game
Elite Systems developed a video game based on ThunderCats. It was released for the Amiga, Amstrad CPC, Atari ST, ZX Spectrum, and Commodore 64. In this game, the player would control Lion-O, who has to defeat Mumm-Ra's evil forces and rescue the other ThunderCats.
 The ThunderCats
Lion-O - Lion-O is the Lord of the ThunderCats. He is based on the lion, and wields the Sword of Omens. It has been hinted throughout the series that Lion-O has feelings for Cheetara and vice versa.
Jaga the Wise - Jaga is based on the jaguar. He was an elder warrior, who was once regarded as the greatest of all ThunderCats. He escorted the ThunderCats to safety.
Tygra - Tygra is based on the tiger. He wields a whip-like bolas in combat. He is the architect and scientist of the ThunderCats.
Panthro - Panthro is the second noblest and the second eldest after Jaga. He is based on the panther. He is the strongest warrior in combat, and is a martial artist. He helps Tygra build the vehicles they use on Third Earth.
Cheetara - Cheetara is a female warrior. She is based on the cheetah, and can move at superhuman speeds. Her weapon is a staff that can grow or shrink. She has a sixth sense. It has been hinted throughout the series that Cheetara has feelings for Lion-O and vice versa.
WilyKat and WilyKit - WilyKat and WilyKit are brother and sister. They are based on the wildcat, and are called the ThunderKittens.
Ben-Gali - Ben-Gali is one the new ThunderCats. He is supposed to be based on a white Bengal tiger. Like Tygra, he is fast and agile, and Tygra calls him "brother". It is unclear if he and Tygra are related, or if "brother" is just an endearment. He wields a weapon called the Hammer of Thundera.
Pumyra - Like Cheetara, Pumyra is a female Thunderean. She is based on the puma, and is one of the new ThunderCats. Like the ThunderKittens, she is agile. In combat, she wields a whipcord.
Lynx-O - Lynx-O is one of the new ThunderCats. He is based on the lynx, and is blind. Like Cheetara, he has a sixth sense, although that is different. In spite of being blind, he is a formidable fighter. In combat, he wields a Sonic Reflector.
Claudus - Claudus is the previous Lord of the ThunderCats and Lion-O's father, Claudus ruled Thundera before its destruction. He lost his sight during a war he fought against the mutants of Plun-Darr. In the episode "Return to Thundera," Lion-O is transported back in time to Thundera the day before it was destroyed. He later rescued his father from past versions of Slithe and Vultureman, who were attempting to recover plans for a War-Bot that Claudus' Spies had gotten their hands on; he then proceeded to give these plans to Lion-O, who used them in the present to destroy the mutants' War-Bot. Believed to have died on Thundera while assisting the royal flagship in taking off, he was later found to have been captured by the Shadowmaster. Through a sequence of nightmares, Lion-O eventually learns of his father's imprisonment in the Shadow Realm and is able to rescue him.
Jaguara - Jaguara is an immortal sorceress. She is ancient and powerful. Like Jaga, she is based on a jaguar.