Nostalgia is unstoppable. People just won't simply give up the things they loved from childhood. On many levels, this is a positive thing, as there's plenty of value in many of these childhood favorites and no reason to dismiss them for a perceived childishness. As C.S. Lewis famously stated, "When I became a man I put away childish things, including the fear of childishness and the desire to be very grown up." But what happens when fans or creators demand their old favorites become less "childish" and "grow up" with them? The results vary wildly. This is the story of superhero comics, where series created as children's entertainment in the '40s and '60s are now primarily read by older adults and often inappropriate or impenetrable for kids. Gritty reboots of kids' TV shows might be less widespread, but still common enough to be worth writing about.

For the purposes of this list, we're defining "kids' show" by the mainstream popular perceptions over the long term. Looney Tunes and The Flintstones might have originally been cartoons for adults, but they've been sold to kids for so long that reboots aimed at the original audiences come as a shocker. Jim Henson didn't really think of The Muppet Show as being "for kids" either, but its kid-friendliness painted it as such, and while the original Ninja Turtles comics were dark and edgy, the significantly more famous cartoon was anything but. Here are 10 times making a more "mature" version of a children's program actually worked, and 10 times it ended in ruination.

20 BETTER: IDW TRANSFORMERS COMICS

Starscream smirking from The Transformers franchise

Can Transformers be taken seriously as an adult? Certainly many adults love the franchise, but even fans have to admit the original cartoon, for all its entertainment value, was pretty darn silly. IDW's 13-year run of Transformers comics, however, not only takes these shapeshifting robots seriously, but actually makes it work!

The classic G1 characters are back, but now there's more moral complexity. Villains are complex, heroes make mistakes. Technological obsolescence is used a metaphor for disability, while the mostly male cast became an opportunity to explore gay relationships and even transgender Transformers! The current Transformers: Unicron miniseries marks the continuity's conclusion.

19 WORSE: TRANSFORMERS MOVIES

transformers-the-last-knight

The first of the Michael Bay Transformers movies is watchable, at least. Nobody was expecting brilliance, and the Autobots themselves at least were heroic and sympathetic. Even in that first film, however, the attempts to prove this wasn't a "kids' movie," with obnoxious sexualization and crude humor, proved cringeworthy.

The series has only gotten worse from there. Optimus Prime's become sadistic to the point of sociopathy, the racism and sexism has increased and the stories for the human characters have only gotten more and more boring. These films are neither appropriate for kids nor entertaining for adults. Hopefully Bumblebee, which Travis Knight seems to be steering in a more family-friendly direction, corrects course.

18 BETTER: GI JOE RESOLUTE

It sounded bizarre: what on Earth was a G.I. Joe movie doing on Adult Swim!?! At the same time, G.I. Joe has always been an odd franchise for kids. It focuses on war, yet because of the young audience and need to sell toys, everything tends to get laughably sanitized. The PG-13 G.I. Joe: Resolute was refreshing un-sanitized.

This hour long movie isn't a masterpiece of animation, but its more grounded take on the mythos went over well. Screenwriter Warren Ellis combined elements of both the old cartoon and the comics for inspiration. Director Joaquim Dos Santos is a major talent when it comes to directing animated action, and the fights here have a nice anime-influenced stylization.

17 WORSE: BATMAN AND HARLEY QUINN

batman and harley quinn

Batman and Harley Quinn is a continuation of the classic Batman: The Animated Series, but lacking its spirit. The animation style's the same as the final New Batman Adventures season, as are Batman and Nightwing's voice actors (though not Harley's). Yet where the old kid-friendly series was moody and sophisticated, this PG-13 movie includes a two minute scene of Harley farting in the Batmobile.

A comedic Batman animated movie could have worked, but Bruce Timm's disappointing return to the DCAU too often goes for the cheapest titilation and most embarrassing attempts at humor. Here's a movie trying so hard to prove it's "not for kids" that it actually ends up more immature than the kids show!

16 BETTER: POWER RANGERS COMICS

Power Rangers is a show so deliciously campy that making a "mature"/"serious" version would seem like a futile task (Joseph Kahn's R-rated Power/Rangers fan film is awesome, but only as parody). The comics from BOOM! Studios somehow manage to do just that and succeed.

The comics are not "adults only" by any stretch, but they provide this silly-sounding premise with surprising depth. There's no attempt at strict faithfulness to the show, but rather new, darker story lines that still respect the show's colorful optimism. The 2018 crossover event, "Shattered Grid," served as an epic featuring Ranger teams from different universes and the ultimate evil ranger: Lord Drakkon!

15 WORSE: 2017 POWER RANGERS MOVIE

power-rangers-movie-suits

Watching the 2017 Power Rangers movie is like looking into an alternate universe where Michael Bay went woke. It's respectable that this movie attempts to deal seriously with issues of bullying, disability and sexuality. Good intentions don't make this a good movie, though.

The main problem for most critics was that this adaptation was simply too disjointed. The more serious Breakfast Club-esque material didn't mesh with the loud blockbuster action stuff, and the cruder and edgier content didn't mix so well with the source material. The movie has its fans, but in general it is seen as a missed opportunity.

14 BETTER: SPACE GHOST COAST 2 COAST

Space-Ghost-Coast-to-Coast-Cast

Let it be said that maturity and seriousness are two very different things. The original Hanna-Barbera Space Ghost cartoon took itself seriously, but that doesn't mean any adult viewers could. Space Ghost Coast 2 Coast, Cartoon Network's first original program, took that cheesy cartoon and repurposed it into a hilarious absurdist talk show.

While early episodes never got too edgy content-wise, the comedic sensibility was clearly meant for older pop culture-savvy viewers from the start. SGC2C laid the groundwork for Adult Swim. It spun off into more adult Hanna-Barbera remixes including The Brak Show, Sealab 2021 and Harvey Birdman: Attorney at Law (it also inspired the original series Aqua Teen Hungerforce).

13 WORSE: 2014 NINJA TURTLES MOVIE

Teenage Mutant Ninja Turtles Live-Action Megan Fox

The 2014 Michael Bay-produced Teenage Mutant Ninja Turtles movie didn't go as extreme with edgy content as the Bay-directed Transformers movies. Having Nickelodeon Movies on as a production company will guarantee that. If not for marketing, this actually could and possibly should have gotten away with being more extreme. The original comics certainly relished the ridiculous ultra-violence.

As is, this film was mostly just bland. The designs were ugly, and the tone was lacking. It wasn't fun but couldn't possibly be taken seriously either. The sequel abandoned any pretense of seriousness and was slightly better reviewed as a result. It was only a very slight improvement, though.

12 WORSE: THUNDERCATS: THE RETURN

thundercats the return

Many Thundercats fans are up in arms now over the wacky, "childish" upcoming reboot Thundercats Roar. Before Roar, though, the most controversial piece of Thundercats media was detested for going too far in the opposite direction. Thundercats: The Return was a Wildstorm comic miniseries so relentless dark it almost sounds like a parody of gritty reboots.

The Thundercats have been defeated. Mumm-Ra is a predator with scantily-clad slaves. Cheetara gets enslaved and assaulted by mutants and blames Lion-O for it. Everything's drawn in the most leering and gross manner. This is not how one would sensibly adapt a children's show to a comic!

11 BETTER: SAMURAI JACK SEASON 5

Samurai Jack past vs future

Samurai Jack was perhaps the easiest series to retool from a kids' show to an adult one. The original four seasons' meditative pacing, philosophical leanings and over-the-top violence made it feel unlike most other kids' shows. Really the only reason it got away with a TV-Y7 rating was because all the enemies were robots rather than humans.

Forcing Jack to face human enemies was a natural way for the fifth season, made 15 years later on Adult Swim, to up the ante. The emotional stakes could be higher than ever before without feeling at odds with what made the series appealing to older viewers in the first place.

10 WORSE: THE REN AND STIMPY ADULT PARTY CARTOON

ren and stimpy adult party cartoon

The original Ren and Stimpy pushed the edges of what a "kids' show" could get away with to the extremes, becomingly extremely popular with adults in the process. The promise of a Ren and Stimpy revival for adults sounded promising on paper. In practice, it turns out the kid show's censorship was what kept the old show watchable.

There were seven episodes made of The Ren and Stimpy Adult Party Cartoon, but only three of them actually aired on Spike TV, the rest shuffled off to DVD years later after being completed way over the deadlines. A cartoon that had once been witty and at times even sweet became needlessly offensive and mean-spirited.

9 BETTER: THE FLINTSTONES COMICS

Flintstones-DC-Comics

The original Flintstones might have been a primetime sitcom for adults, but very little Flintstones-related media since has aimed for maturity. The Cartoon Network special Flintstones on the Rocks brought the family back to their roots, but it's Mark Russell and Steve Pugh's Flintstones comic for DC that really made it worthwhile for adults to care about these characters.

Using the dawn of civilization as a means to satirize every aspect of modern society, this series is too dark for kids, but laces the darkness with the right level of humor for older readers to enjoy. There's at least one moment in each of the 12 issues that will leave you with your jaw dropping at the audacity.

8 WORSE: SCOOBY APOCALYPSE

Scooby-Doo-DC-Comics

DC's radical re-imaginings of the Hanna-Barbera characters have been successful for the most part. Not all of these reboots have been equally praised, however. Scooby Apocalypse didn't actually get terrible reviews. Fans balked at the ridiculous premise and hipster character designs initially, but many critics said it was better than it looked.

That's damning with faint praise, however, given just how divisive its look became for fans. Response in the end was ultimately mixed. Considering the characters were the main things people liked about the old Scooby-Doo cartoons, changing them so drastically wasn't a formula for a hit. Scooby Apocalypse isn't the absolute low point in the franchise, but it's also far from the high point.

7 BETTER: JEM AND THE HOLOGRAMS COMICS

Jem And The Holograms singing in the Jem And The Holograms comic

IDW's Jem and the Holograms comics aren't "adult" in the same way as a lot of the other entries on this list. The language is slightly saltier and the content mildly edgier, but it's only going from a G to a PG. Kids can enjoy the series just fine. It is, however, more mature than the original cartoon was, in as much as, unlike the original cartoon, it also wants to appeal to older readers.

Kelly Thompson and Sophie Campbell created this reboot, which lasted from 2015 to 2018. There are three spin-off books: The Misfits, Dimensions, and Infinite. The goal was to make something adults who grew up with the cartoon could enjoy now. The cast was more diverse, and the characterizations more three-dimensional.

6 BETTER: EXIT STAGE LEFT: THE SNAGGLEPUSS CHRONICLES

snagglepuss-header

Has anyone actually watched a Snagglepuss cartoon in the last decade? Pretty much the character's only legacy in pop culture has been jokes about his homosexual affectations. Hot off the success of The Flintstones, Mark Russell set to work writing Exit Stage Left: The Snagglepuss Chronicles, turning this joke into a serious exploration of McCarthy-era homophobia.

Snagglepuss is reimagined as a Tennessee Williams type, a barely closeted playwright being targeted by the House Un-American Activities Committee. Huckleberry Hound and Quick-Draw McGraw are also struggling with their identities. Humor's almost beside the point in this surprisingly serious and affecting historical drama that just happens to involve oddly-colored talking animals.

5 WORSE: BOO-BOO RUNS WILD

boo boo runs wild

Three creators happen to have two entries on this list. Mark Russell has two on "better" side, while Michael Bay and John Kricfalusi both have two on the "worse." Boo-Boo Runs Wild -- the most infamous of John K.'s three Yogi Bear cartoons -- is better than the Adult Party Cartoon by virtue of some actually funny gags, but overall this cartoon is poorly paced and excessively disturbing.

As a joke, the premise of Boo Boo reverting to his animal instincts could be hilarious, but it's dragged out too long to be funny and it's too shallow to work as an actual psychological thriller. The climactic wrestling scene between Yogi and Ranger Smith had to be censored by Cartoon Network (the uncut version was too "suggestive").

4 WORSE: THE MUPPETS 2015

the-muppets-abc-2015

It should have been amazing. The Muppets always had adult appeal, so it shouldn't have been that difficult to give them a successful primetime sitcom. The characters' first primetime show since Muppets Tonight ended in 1998, ABC's 2015 The Muppets series arrived with a promising test reel and a ton of media hype over the "break-up" of Kermit and Miss Piggy. The actual show itself, however, fizzled out.

At least in the first half of the season, the comedy was lacking, the mockumentary format was bland and the characters were uncharacteristically mean to each other. A mid-season retool tried to iron out some of the kinks and bring more classic Muppet zaniness, but by that point the viewers had left and the show got canceled.

3 BETTER: DOCTOR WHO

Peter Capaldi as Doctor Who

This is one of the more subtle examples, not so much changing demographics as shifting and expanding them. Doctor Who has always been intended for kids, but as the years have gone by, it's reached harder for older fans and become less appropriate for younger ones.

The early years were actually meant to be educational for children, though that didn't last. The show increasingly dealt with more mature political stories in the Third Doctor era, while the Sixth Doctor arguably got too dark. Several episodes from the series' revival era from 2005 onward have been deemed inappropriate for kids under 12 by the ratings board, and spin-off series Torchwood is flat-out NOT for kids (though not better than the original).

2 WORSE: CANCELED 2003 LOONEY TUNES REVIVAL

2003 looney tunes

In 2003, the Looney Tunes were poised for a major comeback. Not only was there the new Looney Tunes: Back in Action movie, but Warner Bros. was set to start releasing new Looney Tunes shorts to theaters! Alas, it wasn't to be. Back in Action bombed at the box office, and only six of the new shorts were finished, the majority unreleased. Also, the new shorts were not well-received!

While conceived as a return to Looney Tunes' more adult-centric roots, the way producer Larry Doyle went about handling the material was all wrong. The animation itself was incredibly divisive and the violence often felt more like Itchy and Scratchy than Looney Tunes. Let's hope the new Looney Tunes Cartoons project's more successful!

1 BETTER: TOONAMI

toonami tom 5

April 1, 2012 was the night a million '90s kids rejoiced: Toonami was back! The night featured a bunch of old classics plus new segments from hosts TOM and Sara (now able to curse)! That Adult Swim April Fools prank got such a positive reception that the block ended up returning permanently. The revived Toonami's lasted six years with no end in sight.

Toonami introduced many children and teenagers to the wonders of anime back in the day, but most of the shows had to be censored. The new Toonami airs classics like Dragon Ball Z and Naruto completely uncut while also introducing shows like Deadman Wonderland and Jojo's Bizarre Adventure, which could never have aired on the old block.