Played with in A Bug's Life in form of the junior ants. First, they make a painting of the good warrior bugs and bad grasshoppers battling, and they painted one of the good guys dead because their teacher said it would be more realistic that way. Then, they perform a play of the battle, in which apparently, EVERYONE dies.
They started to show death in the Cars series films, from the gruesome end of Rod "Torque" Redline to the offscreen death of Doc Hudson.
Transformers: The Movie (1986) was famous principally for introducing this phenomenon to millions of Saturday-morning TV fans, when Optimus Prime dies, along with Megatron, Starscream, almost all the Autobots and an entire planet of Red Shirts in the first ten minutes, followed by the pointless on-screen maiming of several more robots including the last survivor of aforementioned planet for good measure, just to impress upon young'uns that Fiction Is Not Fair.
The animated series Exo Squad also used this trope, inspired by Macross and Robotech, quite daring for the time.
Tigatron and Airazor die, come back as Tigerhawk, and then almost immediately die again, this time for good.
Inferno and Quickstrike get toasted by their own boss. Depth Charge and Rampage go up in an immense explosion. Tarantulus gets hoisted by his own petard. And this is only counting deaths that lasted.
It's easier just to say that 22 characters were introduced (Including a fusion of two previous characters and a clone of another previous character) and that only eight of them survive to the end of the series (Optimus, Rattrap, Rhinox, Cheetor, Waspinator, Megatron, Blackarachnia and Silverbolt).
Beast Machines, the sequel series to Beast Wars, trims Rhinox, Megatron, and Optimus from the surviving eight. The death count of its new arrivals is harder to calculate; it depends on whether or not taking a character created by the extensive reprogramming of an old one and reverting him to factory settings counts as death. The new character definitely permanently ceases to be, but you may not consider that to be "dead." If it is counted, the death toll of Beast Machines new arrivals just tops 50%.
Transformers Animated was also pretty brutal. In the first season finale Megatron kills Starscream with the Allspark key, although he gets better a few episodes later. In the third season it got worse.
Blurr is crushed into a cube by Shockwave in Transwarped, Master Yoketron is left to die in Prowl's arms by Lockdown, Prowl sacrifices his life to stop the Lugnut Supremes from blowing up, and Starscream dies after the Allspark fragment keeping him alive is sucked out of his head. Since this was the final episode of the show, he probably didn't get better, though the comics show Blurr having survived.
There's also the sorta-deaths. Ultra Magnus is beaten nearly to death by Shockwave and we never do see him wake up from his coma (Word of God: Had they gotten a season four, Magnus would have bought it and Sentinel would have taken his place, and the dangerous acts he commits in his hubris would have only escalated.) and the Constructicons are blown up, with only Scrapper seen to survive. There's also the business with the gathering of the Allspark fragments. Since many of them had brought other Transformers to life and removing Starscream's fragment killed him, he may not have been the only casualty. Word of God says Wreck-Gar survived, but hasn't specified the fates of anyone else brought to life by an Allspark fragment. We're given hope in the fact that all the Allspark fragments were clearly not collected (Prowl's sacrifice was necessitated by the fact that not enough were gathered, and the reconstituted Allspark looks barely even half-complete, in fact - they left enough fragments out there to make the hoped-for comic continuation able to still use them as a plot point.)
The makers of Transformers Prime have said that "when we kill a character, we kill a character," and a few surprising deaths have happened. However, no main characters yet as of the season one finale.
Season two has Airachnid tearing Breakdown apart piece by piece. MECH then used parts of his body to build Nemesis Prime. He's Dead Jim.
And near the end of season two, Megatron blows a hole in Dreadwing's torso rather than let him kill Starscream. There's more hole than torso, and just like that, a fairly dynamic and important character is gone, and never mentioned again.
By the end of the series, this trope is downplayed. Out of all the Autobots that appeared in more than one episode, only two get killed off (if you include Zombie!Cliffjumper and his flashback episode). Out of all the Decepticons that appeared in more than one episode, only five get killed off (if you include Zombie!Skyquake, and if you believe that the Predacons mauled Starscream to death off-screen).
This is major gimmick of the Total Drama series. Well, technically, not die, but be eliminated, and can return to the show (and will - in the end of the season, to try to come into the next). Still, the number of active characters is rapidly decreasing and no one is safe, even the most popular and beloved of the characters.
In a rarity for a children's programme, The Animals of Farthing Wood had a fairly high mortality rate, with a lot of the major characters being killed off as the series went on. By the end of the show only a few of the original animals still survived.
Frisky Dingo is one of the few [adult swim] original cartoons in which death is permanent, which it makes liberal use of by killing off both major and minor characters left and right during the second season.
Kulipari: An Army of Frogs downplays this trope. The show doesn't kill off too many characters, but the characters who do die are fairly major recurring characters. Even Queen Jarrah, who is one of the show's main antagonists, is killed before the season finale.
Star Wars: The Clone Wars doesn't touch any of the characters from the films because most of them are Doomed by Canon already, but they are not afraid of introducing an original character and then kill them in the same episode. Jedi and well as clone troopers. Sometimes any original, named character surviving past an episode is a surprise. Sometimes. Each season killed off at least one major recurring character, as listed below.
Season 2 killed off Padme's "uncle," Senator Onacconda Farr.
Ziro the Hutt is killed almost halfway into Season 3. Near the end of the same season, they killed Even Piel, a background Jedi master. This happened just after the viewers were getting past the death of Echo.
Minister Maketh Tua was blown up in her shuttle in the Season 2 premiere. The Season 2 finale would kill off the three remaining inquisitors, the Fifth Brother, the Seventh Sister, and the Eighth Brother, in rather violent fashion, and would possibly kill off Ahsoka Tano, too.
Cool Old Guy and close friend of Ezra's Morad Sumar would unexpectedly die in Season 3 when Thrawn forces him to test a speeder bike they both know has been sabotaged to kill its pilot. Mandalorian bad guy Gar Saxon dies in Season 3 in only his second appearance, Darth Maul perishes in a Single-Stroke Battle with Obi-Wan Kenobi, and recurring Rebel commander Jun Sato takes out both Admiral Konstantine and himself by crashing their flagships into each other.
The entire message of Watership Down being "Small Furry Animals Will Eventually Die Anyway, so get used to it," so it includes all variants of on-screen cute rabbit death in order to drive home the message. It was felt that too many rabbits actually survived the book (Show, Don't Tell!) due to author's reluctance to pull the trigger. So additional doomed characters are introduced and a particularly sympathetic Woobie who played a big part in the novel is highlighted in order to be gruesomely Stuffed into the Fridge near the climax.
Vuk the Little Fox: The beginning of this children's cartoon seems to imply that it will be something cuddly and cute. Besides maintaining a level of cuteness, over a dozen characters (including those with names, personalities and spoken lines) die, either killed by other animals or by human hunters. There is no Carnivore Confusion, as the main hero kills and eats prey on-screen without any trouble.
The Venture Bros., after pointing on at great length in the "Lepidopterists" episode how 21 and 24's Genre Savvy made them indestructible, went on to brutally kill 24 in the season 3 final episode. His burning severed head lands right in 21's hands, making sure everyone knows he's dead for good.
And let's not forget the titular brothers themselves, who were killed at the end of Season 1. For awhile, this seemed to be final, until they got better when the second season finally started, two years later.
Since The Simpsons' Halloween episodes aren't part of the show's canon, the writers frequently end up killing off lots and lots of characters (not even the Simpsons themselves are safe.)
In Felidae, it doesn't matter if you're the Big Bad, The Dragon, a pregnant female or the most sympathetic character in the film. You're going down.
Chuck Jones spoofed opera in "What's Opera, Doc?". Saith Bugs Bunny, "What did you expect? A happy ending?" just before he died in Elmer Fudd's arms
The Arkham series inspired Assault on Arkham features the Suicide Squad as the lead characters, with Batman and the Joker taking a backseat this time around. The story takes place after the prequel, Origins, but before Arkham Asylum, and considering that out of the entire squad, Harley Quinn and Deadshot are the only two you see in later games, the last 10 to 15 minutes of the film becomes this.
Something puzzling is that Arkham Origins and Arkham Origins: Blackgate took care to hint at a Suicide Squad feature in the near future, with Deathstroke, Harley Quinn, Bronze Tiger and Captain Boomerang all receiving clipboards that seemed to hint at their inclusion. Of them all, Boomerang and Quinn show up on the team, and ironically are among those who don't die, compared to the newly introduced villains for the Squad specifically for the film, which may or may not be a clue towards a future Suicide Squad game.
Since the series Futurama starts in the year 3000, everyone Fry ever knew (excluding his girlfriend who froze herself) is dead. Also, the crew die at various points of the series, either getting better or just a What If? question, including when all the crew, excluding the Professor, died in the very first episode of the return onto Comedy Central. Fry has also passed through space and time several times.
Roswell Conspiracies: Aliens, Myths and Legends killed off characters with surprising aplomb for a cartoon in the early nineties; many one-shots, named or not — such as the old leader of the Conduit, Kao Lin, and Ti-Yet's old enemy, Su-Ak — bit the dust, but the casualty rate also encompassed several recurring antagonists (like Hanek, Kahn Mort, and Baron Samedi) but several of the good guys as well, most of them towards the end of the series; Mrs. Smith-Heisen is coldly killed by the series' Big Bad, Spot gives its life to contain a nuclear explosion, and Jerich, Ruck (a redeemed baddie), and Logan's adoptive father all sacrifice their own lives battling the Shadoen fleet. Even main characters weren't exempt from this; Trueblood, part of the main cast roster since the first episode, is torn apart by Rinaker (revealed as the Shadoen agent Wraith and the ultimate main villain of the series), and Wraith in turn is conclusively killed off for real at the end of the series alongside the entire Shadoen fleet. Unlike many instances of this trope, when a character dies, they stay dead.