From comic books to toylines to animated movies, most cartoons are based on something from the realm of kid-friendly entertainment. Over the years, a handful of animated series and films have bucked that trend and drawn inspiration from adult-oriented material. While some of these shows found homes on adult animation blocks like Adult Swim, others filtered out their potentially objectionable content and became unlikely Saturday morning cartoon stars. Although some of these properties were defined by bone-chilling horror or bloody ultra-violence, others simply dealt with adult concerns that made an awkward fit for an adolescent audience. Perhaps because of this narrative incongruity, few of these cartoons achieved any kind of lasting success, with most becoming half-remembered footnotes in their franchises' lasting history.

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Now, CBR is taking a look back at some kids cartoons based on adult properties. For this list, we'll re-examine some animated shows and movies that were based on adult-oriented movies, TV shows, books, comics and games. This list won't be focusing on animated shows and movies meant for adults or adult-oriented media that stars characters originally meant for children. We'll also be looking at how the adult material and complex themes of these properties were watered down for their animated incarnations.

15 BEETLEJUICE

Beetlejuice cartoon

Tim Burton's 1988 film Beetlejuice dazzled audiences with its charmingly disgusting lead, macabre humor and zany take on the afterlife. While the movie focused on a recently-deceased couple as they navigated their new lives among the dead, the film's focus on mortality was a little too heavy for a kids cartoon.

In 1991, Nelvana Limited's animated series Beetlejuice focused on its title character and the very much alive teenager Lydia Deetz. Over well-received four seasons of 94 episodes on ABC and Fox, the popular cartoon spent most of its time in Beetlejuice's home Netherworld, which was filled with a variety of darkly whimsical creatures. While the show rarely dealt with any ideas of death, it usually followed Beetlejuice as he played pranks in pun, sight gag and gross-out humor filled adventures.

14 CONAN THE ADVENTURER

Conan the adventurer cartoon

Like Hercules and Highlander, the titular star of Conan the Barbarian has spent most of his existence in bloody sword fights with vicious enemies. Since his creation in 1932, Robert E. Howard's character has starred in several multimedia adaptations including a pair of successful films in the 1980s that starred Arnold Schwarzenegger as the brutal Cimmerian.

Despite the films' graphic violence, Jetlag Productions and Sunbrow Productions took young viewers to the Hyborian Age with 1992's Conan the Adventurer. In the show, Conan and his allies battled Set, the sorcerer Wrath-Amon and their shapeshifting Serpent Men. While the series received mild praise for capturing elements of Howard's Conan, the cartoon's Conan was less violent and more guided by modern morality than his counterparts in other adaptations. Although this syndicated series was canceled after two seasons totaling 65 episodes, it spawned a short-lived continuation, Conan and the Young Adventurers on CBS in 1994.

13 THE MUMMY

The Mummy

Before this summer's The Mummy, the iconic monster's last major role came with a trilogy of Universal Pictures films starting in 1999. While these Brendan Fraser-starring films were filled with quippy action and impressive CGI set pieces, they still had their fair share of horrific moments that were a little intense for an adolescent audience.

On Universal Cartoon Studios' The Mummy: The Animated Series, those images weren't nearly as frightening. Starting in 2001, the Kids WB! cartoon followed the O'Connell family and their cinematic foe Imhotep, the titular Mummy, and his undead forces. The second season of the show focused more on the Medjai, a sect of warriors who fought the Mummy. Although the adventure-oriented cartoon received decent reviews, it failed to connect with audiences and was canceled after 26 episodes.

12 ROBOCOP: THE ANIMATED SERIES

Robocop in the animated series

Paul Verhoeven's 1987 film RoboCop became a surprise hit with thanks to its biting social commentary and ultra-violence. While that film earned its R-rating, its toyetic lead character was a perfect action hero for an adolescent audience. With a classic origin fit for a superhero and an array of hi-tech weapons, Officer Alex Murphy was destined for Saturday morning cartoons.

In 1988, Marvel Productions and AKOM Productions launched RoboCop: The Animated Series. RoboCop's adventures were far less violent and focused on the more science fiction-oriented aspects of the franchise. Although the show's writing received some minor praise for its relative complexity, lasers took the place of bullets in the show's gunfights. While RoboCop worked with his cinematic partner Anne Lewis on the show, the cartoon's accompanying toyline introduced the Ultra Police, a group of cybernetically-enhanced officers. The syndicated show was canceled after one season of 12 episodes.

11 SWAMP THING

swamp-thing-cartoon

In the 1970s and 1980s, Swamp Thing was one of DC Comics' most exciting titles with its formative brand of sophisticated suspense and psychological horror. In 1982, the plant-based creature that used to be Alec Holland jumped onto the big screen in a film directed by Wes Craven. That film's moderate success warranted a more comedic sequel, The Return of Swamp Thing in 1989 and a darker live-action series in 1990.

In 1990, DiC Entertainment added to this unlikely media empire with the animated series Swamp Thing. As one of the first children's programs on Fox, the show followed Swamp Thing and his allies as they battled Anton Arcane and his freaky Un-Men. With a vaguely environmentalist message and outlandish creatures, the show owed more than a little to Captain Planet and the Planeteers and Teenage Mutant Ninja Turtles. Despite an accompanying toyline, the series was canceled after five episodes.

10 LITTLE SHOP (OF HORRORS)

Little Shop of horrors

Like Swamp Thing, Little Shop of Horrors is another plant-based horror franchise. In 1960, director Roger Corman started the franchise about people-eating plants with a darkly comical B-movie. After that film became a cult classic, it became the basis for a successful musical in 1982. In 1986, Frank Oz turned that musical into a horror comedy about a vicious alien Venus flytrap called Audrey.

In 1991, Fox's Fox Kids programming block gave plant-based horror another try with the animated series Little Shop. In that Marvel Productions show, a teenager named Seymour planted an ancient seed that grew into the talking plant Junior. Instead of eating people, the zany plant helped Seymour and his friends solve their problems through the power of song. Despite musical interludes with a rapping plant, the series was canceled and quickly forgotten after 12 episodes.

9 HERCULES & XENA

Hercules Xena Cartoon

Throughout the 1990s, Hercules: The Legendary Journeys became one of the most syndicated shows of all time. While the long-running adult-oriented action series was a massive success, it was eclipsed by its even more successful spin-off, Xena: Warrior Princess. In 1997, Disney's unrelated, song-filled Hercules became a blockbuster with its light-hearted, musical take on Greco-Roman mythology and spawned an animated series in 1998.

Not to be outdone, Renaissance Pictures and Universal Cartoon Studios gave Hercules and Xena their own all-ages animated feature with 1998's Hercules & Xena: The Battle for Mount Olympus. In that direct-to-video feature, Hercules and Xena fought a group of Titans led by Hercules' antagonistic mother Hera. Along with the main cast of both shows, Kevin Sorbo and Lucy Lawless reprised their respective roles as Hercules and Xena in this moderately well-received film.

8 HIGHLANDER: THE ANIMATED SERIES

Highlander cartooon

In 1986, Highlander introduced audiences to the Immortal warrior Connor MacLeod. As his story continued through a few more feature films, the franchise also spawned a successful, long-running live-action syndicated series in 1992 that starred another member of the MacLeod Clan, Duncan. Since the decapitation of other Immortals plays such an important role in the franchise's mythology, it seemed fundamentally unfit for children's programming.

In 1994, that didn't stop Gaumont Multimedia from producing Highlander: The Animated Series. While the franchise's other entries pit the Immortals against each other in a never-ending contest, the cartoon's Immortals worked together to rebuild humanity in a post-apocalyptic future. While the show's hero Quentin MacLeod found non-violent ways to share power with other Immortals, the show still featured a higher level of violence than most kids' shows. After one season on the USA Network and another in syndication, the series was canceled after 42 episodes.

7 TOXIC CRUSADERS

Toxic crusaders

With graphic sex and violence, Troma Entertainment's The Toxic Avenger became an instant cult classic upon its release in 1985. That film and its three campy sequels starred Melvin Ferd, who was doused in toxic waste and became the deformed, super-strong hero, the Toxic Avenger. Despite the film's content and Troma's raunchy reputation, the character led a group of mutated heroes in Toxic Crusaders.

In the Troma and Fred Wolf Productions cartoon, Toxie and his equally mutated allies fought coackroach aliens from the planet Smogula who sustained themselves on pollution. While the series still featured some adult humor, it featured a talking mop and was far more kid-friendly than its cinematic counterparts. Although the syndicated show spawned a toyline, it was lost in the mix of the era's environmentalist cartoons and was canceled after one season of 13 episodes.

6 ROBOCOP: ALPHA COMMANDO

Robocop Alpha Commando

While RoboCop's first cartoon didn't last too long, the adventures of Alex Murphy continued on across other forms of media. Before Robocop's cinematic reboot in 2014, the character starred in two sequels in the 1990s, which both featured work from comics legend Frank Miller. In 1994, RoboCop starred in a live-action syndicated series that was geared towards younger audiences.

Even though that show was canceled after one season, RoboCop's all-ages adventures continued in the animated series RoboCop: Alpha Commando. Like the other cartoon, this RoboCop was far less violent than his cinematic counterpart. The MGM Animation series took place in a robot-filled 2030, where RoboCop was reactivated to battle the forces of the terrorist group D.A.R.C. Although RoboCop's suit was filled with new gadgets like roller skates and a parachute, the syndicated series didn't connect with audiences and was canceled after one season of 40 episodes.

5 MOBY DICK

Moby Dick cartoon

Although Herman Melville's Moby Dick stands as one of the finest pieces of literature ever produced, it's not exactly the most kid-friendly tale. While the story of Captain Ahab's obsession with catching the white whale is well-known, the novel's grueling depiction of the 18th century whaling industry would either bore or horrify younger readers.

Decades before Free Willy introduced kids to the benefits of befriending whales, Hanna-Barbera introduced young viewers to the white whale in 1967's Moby Dick and the Mighty Mightor. Sharing only a title character with Melville's novel, the show followed Moby Dick, human teenagers Tom and Tubb and their pet seal Scooby as they had various undersea adventures. Although Moby Dick teamed up with Space Ghost and made a few other cameos, the cartoon lasted one season of 18 episodes on CBS. Like Hanna-Barbera's other ocean-centric cartoons, the show's characters were parodied in the Adult Swim series Sealab 2021.

4 TALES FROM THE CRYPTKEEPER

tales-from-the-cryptkeeper

In the 1950s, the gory horror of EC Comics titles like Tales from the Crypt was controversial enough to cause a national firestorm. In the 1990s, HBO's live-action horror anthology Tales from the Crypt brought those lurid thrills to a new generation of mature viewers. Considering the notorious pedigree of the franchise, it was an odd basis for a Saturday morning cartoon.

In 1993, Nelvana's Tales from the Cryptkeeper found an unlikely home in ABC's children's programming block. While the animated anthology series was still hosted by the Cryptkeeper, it featured far less violent tales that were approved by child psychologists. Although the show was initially canceled after two seasons totaling 26 episodes, it was revived by CBS for another 13-episode run in 1999. With strict educational guidelines, New Tales from the Cryptkeeper featured more watered-down morality tales.

3 RAMBO: THE FORCE OF FREEDOM

Rambo freedom force

From its musings on the trauma of war to the high-octane action of its later sequels, the Rambo franchise has had a varied history on screen. After the success of the 1982 hit First Blood, Sylvester Stallone's John Rambo morphed from a haunted Vietnam War veteran into a gun-toting pop culture action hero.

After G.I. Joe: A Real American Hero achieved tremendous success with patriotic paramilitary heroes, Ruby-Spears Animation gave Rambo his own cartoon in 1986. In Rambo: The Force of Freedom, Rambo and his elite team took on the Cobra-esque organization S.A.V.A.G.E. Like some of the Rambo films, its title character only used violence as a last resort and mainly tried to outwit his opponents. Unsurprisingly, the series completely ignored Rambo's history in Vietnam and shied away from any kind of lasting physical injuries. After a toyline and one season of 65 episodes, the syndicated series was canceled.

2 ROUGHNECKS: THE STARSHIP TROOPERS CHRONICLES

Roughnecks starship troopers chronicles

Despite its campy tone, Paul Verhoeven's 1997 film Starship Troopers hid a surprising satire underneath its gory alien bug-fighting action. While Robert Heinlein's 1959 novel of the same name glorified the militarization of its society, Verhoeven's adaption turned the basic plot into a biting critique of fascism.

In 1999, the animated series Roughnecks: The Starship Troopers Chronicles combined aspects of the novel and film while removing all of the political overtones. In the Columbia Tristar and Sony Pictures' CGI-animated series, Johnny Rico led a Mobile Infantry squad, the Roughnecks, on various missions against the alien bugs. While it toned down the film's violence, it still targeted both younger viewers and older fans. While it gained a fairly dedicated cult following, the syndicated show only lasted one season of 40 episodes. Due to various production difficulties, the show never reached its planned conclusion and was canceled without a proper ending.

1 MORTAL KOMBAT: DEFENDERS OF THE REALM

Mortal Kombat Defenders of the Realms

In the 1990s, Mortal Kombat and its sequels were notorious for brutal, bloody beat-downs and gruesome Fatalities. As a lightning rod for controversy about violence in video games, the franchise wasn't the ideal basis for a Saturday morning cartoon, but that didn't stop Film Roman Productions and the USA Network from making Mortal Kombat: Defenders of the Realm in 1996.

Set loosely after the events of 1995's Mortal Kombat movie, the series followed a team of Earth's Kombatants as they fought the invading forces of Outworld. Despite a decent-sized cast of characters from the franchise's early games, the show toned down the game's extreme violence and lacked major fighters like Johnny Cage. With bloodless energy blast-focused battles, the show received fairly negative reviews and was canceled after one season of 13 episodes. The show's only lasting legacy was the debut of  the sorcerer Quan-Chi, who became a fairly major character.

Stay tuned to CBR for all the latest on comics and cartoons. Let us know what your favorite kids show based on an adult property is in the comments below!