Moral Orel started as a goofy and over-the-top parody of shows like Davey and Goliath. They've slowly become much darker, focusing less on more lighthearted and humorous plots and delving into the character drama that comes from living in a community where everyone hates each other and are only loosely held together by a religion many of them secretly resent.
The third season episodes are frequently just downright depressing (with only a couple jokes made), with episodes dedicated to fleshing out secondary characters and showing how messed-up everyone's life (especially Clay's) is. The commentary bits before the episodes even have one exec saying they cancelled the show because they didn't want Dino to do anything worse to Orel. On the other hand, some episodes can be quite uplifting, like "Dumb" which ends with Nurse Bendy getting rid of her weird teddy bear family and spending time with her real son Joe (specifically making weird face all throughout the credits) and "Closeface" which ended with Orel and Christina enjoying a dance while Reverend Putty helps Stephanie (his daughter, who reveals he knew was gay) get over a girl that didn't really like her and they decide to go look for dates together.
The show reaches its arguably most dramatic and depressing moments in the episode "Numb" which has nerry a joke in it. The whole episode centers around Bloberta realizing that she cannot achieve sexual pleasure from the various power tools she uses to masturbate with. Being absolutely repulsed by her husband at this point, she goes on an unsuccessful quest to find a man in town that she can have an affair with. The episode ends with a drunken Clay returning home to witness Bloberta break down in tears after Orel asks her why she married him. After noticing him, she immediately freezes up and returns to her cold, distant persona and the two climb into their separate beds without a single word. All of this while The Mountain Goat's song "No Children" plays. Remember when this show used to be about accidentally resurrecting zombies?
Certain events in the third season premiere of Transformers Animated, most notably the whole Blurr crushed into a cube and the Autobot High Command thinking that ethical guidelines are optional thing, indicate they're going that way.
It did, mostly due to Darker and Edgier kicking in, but even from the second episode of the first season it was fairly clear the show wasn't going to be totally fluffy.
The original series did this starting with The Movie, which bumped off Optimus, Starscream, and several other major characters. It got darker still in the Japanese-only Headmasters season, where Optimus, Ultra Magnus, and Galvatron were Killed Off for Real.
Avatar: The Last Airbender gets more aangst in each season. This is more the characters coming to realize things are bad rather than the plot getting heavier. After all, by the second episode, the show had established the lead character as the lone survivor of a genocide. The series also started adding far more dangerous enemies, going from the PrinceZuko and Admiral Zhao in the first season to Zuko's sister PrincessAzula in the second season and father FirelordOzai in the final season.
Sequel series The Legend of Korra pushed this even further. While the previous series took care to highlight silver linings in even the bleakest of scenarios, Korra had a number of episodes end in utter failure and despair. In the first twelve episodes.
You know what makes for quality family entertainment? A fraternal suicide-murder, that it can be argued the murdered brother had purposely set up after his defeat.
In the final episode of season three Korra ends up in a bit of a pickle when she has to keep herself from activating the avatar state wile slowly being KILLED by a metallic poison just so the avatar cycle would not end forever. She is ultimately saved but still ends up in a wheelchair and unable to smile for several weeks. GEEZ series, you really don't need to get any darker after this!
12 oz. Mouse started out as an immature comedy that appealed to stoned 12 year olds, and quickly became a something that defies description.
The series started out defying description and went off from there.
Well, the first couple of episodes are just Fitz wandering around getting hit by cars and stuff like that. Afterward the show started taking on Mind Screw elements, Continuity, Characterization and became the Cult Classic its fans loved. If I had to pin-point the exact moment this happened, it would be in the end of episode 3, when Fitz asks where Skillet is, before cutting to Skillet, tied to a chair with a ballgag in his mouth, in a building filled with pictures of him, and the new guy standing over him.
MTV's Daria was originally mostly about the title character and her friend facing the stupidity of High School with a half-smile and a snarky comment, always beating the system, though the serious side of it was always beating under the surface of the comedy. The show started delving into the deeper issues faced by high school students, ending the first season with an episode where the girls deal with the death of someone they both loathed and Daria's attitude is both a blessing and a curse. The second season largely dealt with things from a more comedic perspective again, but spent more time on looking at the goals of the invidual characters and the final episode was again a serious examination of Daria's attitude and whether that was what she wanted for her entire life. Season 3 started into this full bore and ended with the first real conflict between Daria and Jane. The final two seasons entirely covered the turbulence of the two girls falling for the same guy, Daria's own confusion over handling her feelings for crush Trent and boyfriend Tom, and the reality of the end of high school and what it would mean for herself, her family, and her friends. It's debatable whether or not this went too far in the final two seasons, but even the staff copped to setting out to do this in Season 3 (though the rather serious finales of the previous two seasons set the stage for the eventual shift into full on Dramedy).
ReBoot was originally about computer components protecting their town in a mostly comical fashion. When Bob was lost in the Web at the end of Season 2 and Megabyte begins an active battle for control of Mainframe, the series got much more serious, but still retained its adventurous charm. For the 4th season it starts off with the Daemon Wars only to conclude that and turn sharply back into a more comedic show. THEN Megabyte is still alive and using his new Trojan powers trickes everyone into thinking he is Bob. He almost marries Dot, infects Mainframe and seems to have won. The series is like a mood yoyo.
The fourth (and for about four years, final) season of Futurama dipped in this territory. While still overall episodic and comedic, "The Why of Fry" revealed that there had been a subtly done "arc" all along, and episodes like "Jurassic Bark" and "Leela's Homeworld" were outright tear jerkers.
Starting with the movies, and continuing with its return to a regular series format on Comedy Central, the show has maintained itself as a comedy series, albeit with some changes in tone. It has begun to address socio-political issues in a more overt way than it previously had, and the humour has become noticibly darker and more mature. However, there is still plenty of comedy to go around.
Metalocalypse started out as a total screwball absurdist comedy (in typical Adult Swim fashion) involving the world's most popular metal band with a loose at best thread of plot. Then characters started getting fleshed out, things like child abuse and parental neglect started popping up, and in the second season finale the band is attacked in their own compound, Mordhaus, by a small army of soldiers brainwashed into killing them and anyone who stands in their way. An epic battle ensues, the band's home is set ablaze, and their manager may very well have been killed.
Subtle character development even there. The band had spent the finale verbally abusing Toki, concluding that helping him out would be interfering with his life, and arriving to the fact that they had to be jerks by some insane logic that only makes sense to them. As usual. As Nathan is saving Toki, he says that he doesn't want to interfere, but Toki has been "way too drunk" lately. At the end, they rescue Offdensen from torture at the psychotic mass murderer's hands stating, "That's our bread and butter you're fucking with." They had previously barely noticed Offdensen, besides the fact that he made them do work. They even thought he was their butler.
Season 03 has delved into this in subtle ways too. While it is still pretty much Played For Laughs and sprinkled with the show's typical sadistic humor, many of the band members get some pretty heavy Character Development. Skwisgaar temporarily quits with a desire to find his father, Pickles gets into the root of his substance abuse issues (and singsabout it), and the rather depressing reason why Toki is so enamored with Doctor Rockzo is revealed.
While "Church of the Black Klok" (or the last three or four episodes of season 4, period) gave the Offdensen fans a serious case of emotion while he describes the deep, terrible details of his own death in that usual calm monotone, the prize for perhaps most emotional show of how important Charles really is to his bread and butter shows itself in "Doublebookedklok". Between the boys being legitimately upset at the idea that their manager may hate them after he is FURIOUS over the simultaneously booked gigs in Syria and Israel respectively and their running away as a result (culminating in the second snowbound manhunt of the episode and a Crowning Moment of Heartwarming when Toki actually hugs Offdensen) and the emotional speech he gives to his assistant about how his job is "something worth dying for"...you really get the feeling that Dethklok and his job are the closest things to a real family he has.
And then season 4 happened. Holy shit. Let's do a sorta recap, shall we? Going back to fifteen minutes in length, we now have downright Mood Whiplash as we bounce between our usual jokes, an oncoming FREIGHT TRAIN of the Myth Arc plot, all while the interpersonal relationships between the band become more deeply explored. It doesn't go well for the "Friender Bender" buddy duo of Nathan and Pickles, by the way. Oh, and did you think Toki, sweet, adorable, and horrendously depressing little bundle of moe Toki would be safe from the rampant and violently terrible deaths the series is famous for? Think again. He gets stabbed in the season finale by the former bandmate, Magnus, in his mad obsession with revenge, and his fate (as well as Abigail, the band's new producer, who Pickles still had feelings for) is still as of yet unknown.
Season 1 of Beast Wars started as light, comedic, and episodic. As the season went on, darker story arcs began to appear. By the time the show got to season 2, there was considerably less (though still a decent amount of) comedy, and season 3 was just plain dark. And don't even get started on Beast Machines, which is so dark the sky might not have even ever turned light.
This is another case of Tropes Are Not Bad, however, in that for many, season 2 of Beast Wars is the high point not only of the show in specific, but of Transformers media in general.
Especially the episode "Code of Hero", which ends with the Heroic Sacrifice of Dinobot and is generally regarded as the best episode of the show, and can sit with the best stories across the whole 30-year franchise.
Inverted with the second Teenage Mutant Ninja Turtles animated series, which begins by almost perfectly mirroring the original comic's dark, serialized story arcs (though with more overt humor), but then goes through an entire tonal shift in season 6, becoming more like the older cartoon series.
By contrast, the first series got slightly darker starting with the eighth season, painting all of Manhattan under a dark red sky, having the entire city unite against the Turtles thanks to Burne's propaganda blitz, adding a story arc of the Turtles still mutating and replacing Shredder with a more sinister alien Big Bad named Dregg.
Interestingly subverted by The Venture Bros.. The plot does get deeper and darker, but the comedy just gets blacker. Even utterly serious scenes don't stop with the jokes, the subject matter just shifts.
Really, there is much more hope for the characters now than at the beginning.
The Raccoons is on the "done right" side of this syndrome. Over time, it shifted from by-the-numbers and cartoonish before evolving the characters into more distinct, realistic (by cartoon standards) personalities and more story-driven episodes.
Wakfu is a goofy and lighthearted French children's cartoon that takes a screaming left turn into darker territory during the last couple of episodes, in which a major protagonist is killed, The Bad Guy Wins, and the bad guy loses again and commits suicide. There's also the special episode depicting the villain's Start of Darkness, which was directed by maestro of Deranged AnimationMasaaki Yuasa.
Codename: Kids Next Door began as a show that took mundane kid issues (such as going to school) and blew them up into devices in an ongoing "kids vs. adults" war. The show was fairly comical with no serious plots emerging until the conclusion of the first season (during "Operation G.R.O.W.U.P."). However, as the larger KND organization began to be revealed (initially the show only showed the five members of Sector V), the stories took a turn into deeper and darker territory with backstabs and some much more serious villains (early episodes featured gimmick villains like Count Spankulot but later on you get the very driven KND defector Cree Lincoln who has a vicious vendetta against the organization). The story still dealt with kids problems blown up one-thousand fold (such as teens being jerks to little kids being reinterpreted as teenagers acting as highly-trained field agents for adult villainy) but the plots were less comedy and more action and dramatic.
"Operation A.R.C.H.I.V.E." seems to show this with a parody of verydark "The Second Renaissance" from The Animatrix.
Starting with "Dr. Blowhole's Revenge", The Penguins of Madagascar has become a little less cartoonish, playing up the sci-fi elements (mostly from Kowalski) and the technology a bit more. It's started to reverse a little bit in the latter half of season 2, though.
While South Park is still very much a comedy, its tone has changed significantly over its run. Early seasons were silly and sitcom-like, with a sense of humor reminiscent of Monty Python's Flying Circus and The Simpsons; later seasons became increasingly topical, with most episodes featuring recent political or social issues, while the Black Comedy became even blacker with numerous Downer Endings and increasingly common and graphicviolence. Needless to say, fan opinions are divided regarding when the show was (or is) at its peak.
"You're Getting Old" definitely avoids the Status Quo Is God rule by ending with Stan ending up a "cynical asshole" and his parents separating. The episode's lighthearted beginning did not last.
Invader Zim, of all things, went through some of this right towards the end of the show. Being an episodic comedy with a fair bit of negative continuity for its first two seasons, the third season began to have running continuity, most notably involving Tak's ship. While it still didn't take itself too seriously, the greater focus on sci fi elements, the war against the Irken Empire, and other facets of the Universe promised something beyond the original scope.
On the commentary, they mention that they had been planning more stuff with epic space battles, and it was just as well the show ended because kids weren't interested in that, they wanted comedies in school.
This is the formula for most Teen Titans seasons; they start out light hearted and comedy driven, then become really dark near the end. The most extreme example compared to the rest of the show (the arc itself starts dark and stays there) is season 4, when Raven is used as a portal for her demonic father Trigon and he takes over the world in a hellish apocalypse where all humans except the four remaining Titans turned to stone. (This lasts for three episodes.) It's worth noting that the silliest stories usually came after a particularly dark or scary episode.
Within the arcs themselves, both the season one and two arcs start out very light and end up very serious; the precise turning point in each is about when Slade decides to step out of the shadows. Also inverted with the season five arc, which isn't nearly as dark, ominous, or serious as the season 4 arc which preceded it.
Adventure Time. Compare the first season's pure comedy to the third's larger focus on romance, friendship, and other relationships between the characters.
"Holly Jolly Secrets" has perhaps the most significant example: The Ice King's origins are revealed in his video diary, revealing he was once a antiquarian named Simon Petrikov, who was perfectly sane and had a fiancee, but when he jokingly put the Ice Crown he bought from a Scandanavian merchant, he did something that caused her to leave him, and he never saw her again, the rest of the video diary is a depressing borderline Apocalyptic Log. This reveal can retroactively make even some of the silliest early episodes really depressing.
The show itself has been through this not once or twice, but SIX times. The first season was more of a lighthearted, slice of life comedy show in the vein of The Simpsons and Baby Blues which featured storylines focusing on mainly the family as a whole. The second season continued this formula but shifted it a little in favor of focus on other characters and started to find it's own voice away from The Simpsons. The third season is when the show began developing the characters but focused more on gags and jokes than the previous seasons and became edgier in tone. Seasons 4 and 5 had most of the character's personalities altered and became a show exclusively for telling jokes and gags but retaining some of the heart that the previous seasons had. This was altered again in Seasons 6 and 7 (mainly because the crew members that worked on Seasons 4 and 5 went to work on Phineas and Ferb and the majority of the "charm" those seasons had went straight to that show), where the show became a venue for jokes with very little heart in between and became a little more serious as some episodes had Brian voice Seth MacFarlane's political views. They shifted this again in Seasons 8 onward in exchange for nothing but mean-spirited humor and taking a Darker and Edgier tone to the point of where an episode featuring heart now is very rare.
Special mention should go to the 150th episode "Brian and Stewie", which gradually becomes less comical as the episode goes on.
Star Wars: The Clone Wars has been hit by this, though due to the show's Anachronic Order, things are a lot bumpier. Generally, the first season is lighthearted fun, with a tinge of drama. Then comes the season one finale, ending with a terrorist attack. This sets the tone for most of Season 2, which featured massive scale combat chock full of Family-Unfriendly Violence, suicide, zombies, and child soldiers. Gets even weirder during the season finale again, ending in a three part arc that starts serious, gets bafflingly kid friendly halfway through before diving right back into the darkness.
Season 4 had a few lighthearted episodes where C-3PO and R2 had fun adventures. The rest of the season was filled with violent deaths (one character breaks a mook's neck for pete's sake), scenes of war, and racism towards clones.
Though not particularly sunny to begin with, Transformers Prime has now been hit by this, starting with Unicron's debut appearance and never looking back, particularly in "Crossfire" when Breakdown (one of the most sympathetic Cons) gets violently murdered by Airachnid. It's difficult to say if there's an actual Knight of Cerebus, but the prime candidates might be Unicron or Airachnid, as neither have many funny traits or any redeeming ones.
Agent Fowler, oddly enough, might be a non-villainous Knight of Cerebus. Fowler's position as a government agent and former soldier allows the show to highlight just how destructive the fight with the Decepticons is, and many of his appearances signify a situation getting worse. The human kids have been getting much less screen time in the second season, while Agent Fowler has been getting much more, at least partly because they can do things to him that would jack the rating way up if they happened to children. Even when the kids do appear, they are purposefully being put into much more dangerous situations than in the first season, and crack far less jokes.
The Simpsons. While later episodes tend to have darker storylines with more downer endings, it should be noted several early episodes such as "Homers Odyssey" (Homer is Driven to Suicide), "Bart the General" (Bart gets bullied), "Moaning Lisa" (Lisa gets depressed), "Life on the Fast Lane" (Marge nearly cheats on Homer), "Bart vs. Thanksgiving" (Bart runs away) and "One Fish, Two Fish, Blue Fish, Blow Fish" (Homer thinks he's going to die). Some later episodes do this too, including "Mona Leaves-a" (Homer's mother dies) and "the Squirt and the Whale" (Lisa tries and fails to save a beached whale.
However, episodes from the mid-90s to early 2000s epsiodes vary in balance of humor and seriousness Depending on the Writer.
The first few episodes in Teenage Mutant Ninja Turtles (2012) seemed fairly tame, not unlike the original cartoon. However, "The Gauntlet" was where the lightheartedness came to a complete stop with April's father giving up his potential freedom to help save the city, Bradford and Xever becoming mutants, and all capped off with the Shredder's first encounter with the Turtles and engaging them in a completely one-sided fight, resulting in the four barely escaping the battle and certain death.. It lightened up a little afterwords, but one can still feel the damage was done and that now the series will almost always have some lingering darkness to it. It's only a matter of time before it reaches its predecessor cartoon's level of dark moments.
Sponge Bob Square Pants after the movie things got a lot darker and a bit depressing. This also started before the movie. Such episodes include "SpongeBob Meets the Strangler" (where he is pursued by a sadistic criminal) or "Dumped" (where the episode begins quite cheerful but the development of the episode is pretty Tear Jerker).
The series get enough of this, but deserves special mention "Have You Seen This Snail?", the episode begins quite cheerful, but the closer the main plot is quite serious and get several Tear Jerker moments, too.
Also the infamous episode "One Coarse Meal", when Mr. Krabs exploits Plankton's fear of whales by dressing up as Pearl and scaring him. Sounds funny enough, but the kicker is how Plankton takes it.
Nobody ever thought any incarnation of Scooby-Doo could pull this off. Welcome to Crystal Cove, the Most Hauntedest Place on Earth! On a franchise level, it looks at the people in monsters costumes and decides to treat someone that started causing havoc while wearing a costume like a legitimate danger. In the series itself, the first season finale has the gang split up in light of several betrayals of trust, and while they get back together quickly, the damage had been done.
And then the second season comes up and, without spoilers, let's just say it just beat Scooby Doo on Zombie Island as darkest incarnation of Scooby Doo EVER.
The original Kung Fu Panda was a mostly light-hearted comedy with some occasional dramatic moments thrown in. Kung Fu Panda 2 keeps the comedy, but cranks the drama waaay up.