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* Some ''WesternAnimation/TheLoudHouse'' promos can be spoilerific. [[https://www.youtube.com/watch?v=o7pd9uGrgrU This promo]] gave away the ending of "No Spoilers", and [[https://www.youtube.com/watch?v=1ES0z6scHh4 this promo]] gave away the climax AND the ending of "Snow Way Down", too.
* The episode "Squid Noir" From ''{{WesternAnimation/SpongeBob SquarePants}}'' was completely spoiled, when Nickelodeon launched a block called "You Bring The Color", and the website called youbringthecolor.com to use the pictures from the end of this episode so kids can color the characters from the ending. No one even knew, until the altered ending got aired.
** The made-for-TV movie ''Atlantis Squarepantis'' spoiled the climax where [[spoiler:Plankton finds out he stole a tank that shoots ice cream.]] It wasn't like it was in a montage or anything either, they blatantly displayed it up front because they thought the punchline was funny enough to include. It got even worse when they put a CommercialBreakCliffhanger right before this moment.
* Played with in ''{{WesternAnimation/Archer}}''. The first episode of season 5 ends with a FantasySequence of Archer's that serves as a trailer for the rest of the season. It did include some genuine spoilers, but they were interlaced with things that never happened (like [[spoiler: Cherlene getting kidnapped]]) and things that happened in completely different circumstances (like [[spoiler: Lana going into labor]]).
* When ''WesternAnimation/BatmanTheAnimatedSeries'' originally aired on Fox, some of its promos could be pretty spoilerific, too. [[https://www.youtube.com/watch?v=PUIE7oEL-ok This one]] outright shows the cliffhanger ending of "Heart of Steel, Part 1" in it.
* Promos for the first two ''[[Toys/BionicleGeneration2 Bionicle: The Journey to One]]'' episodes spoiled most of the ending by showing the sought-after Mask of Creation in the hands of the villains, from the very last scene. The only things not to get spoiled were [[spoiler: Umarak kidnapping Ketar and mutating into a hulking beast upon putting on the mask]], but these were already SpoiledByTheMerchandise aynway.
* Pick a trailer, any trailer, for any episode of a 2010s Creator/CartoonNetwork series. You've basically seen the entire episode in under 30 seconds.
** For a particularly JustForFun/{{egregious}} one, the beginning of the trailer for ''WesternAnimation/TeenTitansGo'''s "Justice League's Next Top Talent Idol Star" (no, that's not a typo) Shows that Robin, Raven, and Cyborg were the final contestants.
** And if the trailer for "Giant Woman" is any indication, ''WesternAnimation/StevenUniverse'' might be starting to fall victim to this too.
*** A promo shown during [=StevenBomb=] 4 showed a clip from "Barn Mates" spoiling [[spoiler:the return of Lapis Lazuli]], which aired a full four months later.
** A less spoilery example, but one promo for the ''WesternAnimation/RegularShow'' episode "Go Viral" ''actually showed the ending of the episode'' (more specifically, the Farting Bear that was a RunningGag in it [[spoiler:landing on Muscle Man]]).
*** Before the ''WesternAnimation/ThePowerpuffGirls2016'' Episode Power-up Puff aired The [[https://www.youtube.com/watch?v=nb920xI_NrM Teaser]] [[spoiler:shows Blossom finally getting her new powers.]]
*** The Russian version of Cartoon Network has proved to be extremely spoiler filled twice so far. First, it revealed ''WesternAnimation/{{Unikitty}}'' before Cartoon Network announced the show, and then revealed what Bliss looked like prior to the Power of Four PGG 2016 special.
* The trailer for the series finale of ''WesternAnimation/DannyPhantom'', "Phantom Planet", was almost completely spoiled just through the commercials. In ''one commercial alone'', it was spoiled, though being ''outright stated by the narrator'', that Danny loses his powers, gets them back again later, gets together with Sam, and enlists the help of every other ghost in the series to stop the Disasteroid.
* The trailer for "Heather Report" in ''WesternAnimation/DragonsRidersOfBerk'' completely reveals that Heather is TheMole, working for [[BigBad Alvin]].
* During its original airing on WesternAnimation/TheDisneyAfternoon, the trailer for Part 1 of the ''WesternAnimation/{{Ducktales}}'' GrandFinale, "The Golden Goose", showed the cliffhanger ending of Huey, Dewey, and Louie getting turned into gold statues.
* In the ''WesternAnimation/FamilyGuy'' episode "[[Recap/FamilyGuyS8E19TheSplendidSource The Splendid Source]]" (after Cleveland had left for ''WesternAnimation/TheClevelandShow''): "Cleveland! Who would have thought we would run into you? Except everyone because Creator/{{Fox}} [[LampshadeHanging spoiled it in all the promos]]."
* More Creator/DisneyChannel screwing: In a ''WesternAnimation/FishHooks'' episode "Fail Fish", Milo has to pass a test in order to prevent himself from being held back a grade. This would have been taken as a surprise, if only they hadn't shown him [[spoiler:holding the test in his hand while he shouts for joy, implying that he has passed it!]] You might not be able to catch it if you're not paying attention, but it's still there.
* From Disney XD's ''WesternAnimation/StarVsTheForcesOfEvil'', [[https://www.youtube.com/watch?v=NJD0CIP5KVY Promos]] from The Battle of Mewni Spoiled most of the movie, Including the [[https://www.youtube.com/watch?v=Nt-nSh_L-nU Teaser]].
* [[http://www.flickr.com/photos/kerrytoonz/2679457672/ This]] print advertisement for ''WesternAnimation/TheFlintstones'' special "Hollyrock-A-Bye-Baby" shows that Pebbles will have twins.
* Black Phantom's defeat from the ''Toys/HeroFactory'' TV special was spoiled, shot for shot, on an on-line promo vid advertising the cartoon and characters (and their toys) on the Franchise/{{LEGO}} website.
* Nickelodeon showed various commercials of scenes leading up to the release of [[WesternAnimation/HeyArnoldTheMovie The Movie]] of ''WesternAnimation/HeyArnold''. One of these completely spoiled that Helga finally confesses her love for Arnold. (They didn't show how he reacted to it, though.)
* The ads for TheMovie and GrandFinale of ''WesternAnimation/KimPossible'' (before it was {{Uncanceled}}), ''[[WesternAnimation/KimPossibleMovieSoTheDrama So the Drama]]'', show the HighSchoolDance moments leading up to the [[RelationshipUpgrade the final kiss between Kim and Ron]], something shippers have been hoping for since Season 1. They didn't even attempt to ShipTease the fans with the RomanticFalseLead, Eric. Obviously they believed fans needed MORE incentive to watch the show.
** As if that wasn't enough, one of said ads actually showed a clip of Kim being shocked by Eric while he had an evil look on his face, which would pretty much give away that [[spoiler:he's really working for Drakken]].
* The trailer for the season finale for ''WesternAnimation/TheLegendOfKorra'' was shown when there was still one episode to go before it, and spoiled that [[spoiler:the Equalists will get control of the city and begin mass bending removal]].
* The [=YESvember=] music video on Nickelodeon's [=YouTube=] channel includes a scene from the ''WesternAnimation/TheLoudHouse'' episode ''11 Louds a Leapin''', spoiling [[spoiler:the reveal of Mr. and Mrs. Loud's faces]].
* A promo for the ''WesternAnimation/{{Motorcity}}'' episode "Like Father, Like Daughter" spoiled the ending in which [[spoiler:Julie agrees to take over [=KaneCo=] should something happen to her father]].
* The trailers for the ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' episode "Magical Mystery Cure" included a clip of Fluttershy saying "You look just like a princess!", completely spoiling the game-changing twist (That everyone already knew about) that occurs the very end of the episode. And then, Hasbro proceeded to [[MerchandiseDriven plaster this plot twist all over all over their commercials and toys.]] Additionally, a sign depicting Twilight Sparkle with wings was actually sighted months before the episode was even announced, but was dismissed by most as an error from the artists.
** To the great annoyance of viewers who had spent most of season 4 (if not longer) awaiting the frequently-referenced Equestria Games [[spoiler:(and especially of Rainbow Dash fans)]], a promo for the final episodes of the season included a very brief clip of [[spoiler:Spitfire crossing the relay finish line narrowly but noticeably ahead of Dash]].
** Also, in the Season 4 finale "Twilight's Kingdom", the Golden Oaks Library, where Twilight has stayed since moving to Ponyville [[spoiler:is destroyed by the new villain]].
** In the Hub trailers for the finale as well, the Royal Sisters and Princess Cadence [[spoiler:lose their Cutie Marks when they transfer their magic to Princess Twilight, leaving them helpless to being made hostages/prisoners of the new villain]]. [[https://derpibooru.org/616737]][[https://derpibooru.org/616744]][[https://derpibooru.org/616753]][[https://derpibooru.org/616454]] In the trailer as well, Twilight is seen [[spoiler:taking off so fast, she leave a crater in the ground, against a [[TheEndOfTheWorldAsWeKnowIt blood red sky]].]]
*** About the only thing the trailer for the finale didn't spoil was [[spoiler: that said villain was a FIM version of classic villain Tirek.]]
** In another instance of using TheReveal to sell more toys, Hasbro announced in 2013 a new set of "Rainbow Power" toys featuring the ponies covered in rainbows. Around the same time, the season 4 premiere introduced a mysterious locked chest whose contents were unknown. At the very end of the season 4 finale, the ponies finally manage to open the chest, and a magical rainbow comes out and makes them change into "Rainbow Power" versions of themselves as a SuperMode, allowing them to defeat the villain. Way to reveal your [[WhamEpisode big end-of-season twist]] early in order to [[MerchandiseDriven sell more toys]], Hasbro.
** In another minor example of the toys spoiling the theme: several months before the first advertisements for season 5 were out, a new set of toys were released, the theme this time being Cutie Mark Magic. Guess what the theme of season 5 is?
** The Discovery Family promo for season 8 features a particularly bad example of this, spoiling lots of big surprises like [[spoiler:Starlight and Sunburst getting called by the Cutie Map, the return of Queen Chrysalis, and Spike getting wings]].
** In ''WesternAnimation/MyLittlePonyEquestriaGirlsMagicalMovieNight: Movie Magic'', the plot involves figuring out who is sabotaging the production of a movie. The synopsis for ''Mirror Magic'' indicates that [[spoiler:Juniper Montage]] seeks revenge. Do the math.
* ''WesternAnimation/PhineasAndFerb'' has the episode "Candace Gets Busted". In order: It starts off as an intimate get-together, she has no problem inviting a few more people, but then it becomes a party, Linda calls the house and says they're coming home. Then guess what happens? [[ExactlyWhatItSaysOnTheTin "Young lady, you are so busted!"]]
** To be fair, if you couldn't guess that was going to happen based on [[SpoilerTitle the title]], well...
*** Then there's "Minor Monogram", where the commercials literally only showed the ending where [[spoiler:Vanessa falls for Monty]].
* The theatrical trailer for ''WesternAnimation/RugratsInParis'' had Creator/DonLaFontaine [[spoiler:proudly introduce Kimi as "the newest Rugrat",]] therefore cluing the viewers in [[spoiler:on how the movie ends (Chuckie's dad marries her mom) and her incorporation into the show]].
* A teaser for the second half of ''WesternAnimation/ScoobyDooMysteryIncorporated'''s second season clearly depicts [[BigBad Professor Pericles]] going OneWingedAngel after becoming the vessel for [[GreaterScopeVillain the Nibiru entity]].
* Parodied in ''WesternAnimation/TheSimpsons'' with an old ''[[ShowWithinAShow Radioactive Man]]'' film reel. A giant missile heads toward Earth, and cuts to a freeze frame while the announcer says, "Will Radioactive Man save the planet Earth? Find out next time!" The freeze frame shows ''Earth being split in half with a giant mushroom butt.''
** That's more a parody of old adventure serials. They routinely ended with something terrible happening (e.g., the hero's car skids off a cliff) and an admonishment to see the next installment to find out how the hero would avoid his terrible fate. Invariably, the next installment would be a [[CliffhangerCopout total cheat]] (e.g., the hero jumps out of the car before it reaches the edge - even though he was ''clearly'' in the driver's seat as the car went over in the previous installment).
** The promos for the episode "How Munched is That Birdie in the Window" spoiled the whole plot of Bart adopting a wounded pigeon and Santa's Little Helper eating it.
** The trailers for ''WesternAnimation/TheSimpsonsMovie'' show the exchange among Homer, Bart, and Russ Cargill near the end of the movie with the "treasure of I'm a weiner" joke. This spoiled the "ToBeContinuedRightNow" joke as the latter takes place before the former in the movie, showing there is more.
** The syndication promo for "When Flanders Failed" had Bart facing the bullies with his "karate skills". The announcer asked, "Will Bart get a black belt or a black eye?", followed by a cut to Bart hanging from a basketball hoop by his underwear.
* Parodied in the ''WesternAnimation/SouthPark'' episode "Professor Chaos":
-->'''Narrator''': Will Professor Chaos succeed? Which boy will replace Kenny? Which adult cast member will [[TonightSomeoneDies die]]? These questions will be answered... [[spoiler:[[ToBeContinuedRightNow right now]]. No, Tweek, and Ms. Choksondik.]]
** Though that may have been intended as a parody for the (in)famous "Who is Eric Cartman's real father?" 2-parter, since a ''lot'' of fans were ticked off when they got the Terrance & Phillip special after waiting for a month, instead of the continuing story.
* ''WesternAnimation/StarWarsTheCloneWars'' has restrained itself fairly well when it comes to foreshadowing Anakin's eventual transformation into Darth Vader, so naturally, Cartoon Network was eager to promote an episode where Anakin has a vision of what he will become. They show us some pretty sweet clips in the promos, but when the actual episode was aired, you realized they showed you the whole scene!
* ''WesternAnimation/StarWarsRebels'':
** The season 2 midseason trailer showed somewhat more of the finale than Creator/DaveFiloni would have liked, in particular [[spoiler:the Sith holocron, the return of Darth Maul and Ahsoka and Vader's duel]]. However, it did not spoil some particularly major plot points, namely [[spoiler:Ahsoka's UncertainDoom and Kanan getting blinded]].
** It's not a surprise to anyone keeping up with the show, but the season 4 trailer has a shot of [[spoiler:Kallus]] in a Rebel uniform, which to anyone only familiar with his character from the first two seasons would be unexpected to say the least.
* ''WesternAnimation/StevenUniverse'' tends to get hit very, very hard with this trope. In the few days after Stevenbomb 4 alone, 2 clips were released on Cartoon Network's UK site as promos that reveal [[spoiler: the return of Malachite and Lapis Lazuli]]. Especially infuriating due to the show's long hiatuses, which meant that the spoilers didn't even appear until almost 4 months later, when the episodes finally aired.
** It's arguably gotten even worse with the "Steven's Summer Adventures" event, in which the network is releasing significant portions of pretty much every episode early as "sneak peeks." In a particularly irritating move, they have also uploaded clips and made news articles surrounding [[spoiler: Bismuth being introduced, in which it is also shown that Amethyst has received another design change]]. It kind of makes you wonder whether any major development in the show will ever be allowed to go un-spoiled ever again.
** Possibly the most notorious case thus far was in May 2018. As part of a miniseries about creating cartoons called "Drawn Podcast", Cartoon Network released an interview with Rebecca Sugar and Ian J.Q. In the video were screenshots of unreleased episodes that were regarded as major spoilers for not just the current season, but possibly even '''the show as a whole.''' Even worse, this came after many members of the Crewniverse begged the fandom not to spoil the upcoming episodes. Needless to say, fans were ''furious'' at the network and [[http://hilaryflorido.tumblr.com/post/173496729353 members of the Crewniverse]] [[http://rocks-tumbled.tumblr.com/post/173528783431/ian-jqs-statement-on-the-leaks were pretty distraught,]][[note]]Ian's original tweet is now deleted[[/note]] and the video was quickly pulled after backlash, then reuploaded without the spoilery parts.
* ''WesternAnimation/TotalDrama'':
** The original trailer for ''Total Drama World Tour'' (back when it was still being called ''Total Drama the Musical'') spoiled Leshawna's elimination; also, if you look quick, it also spoils Ezekiel's elimination as well, as you can see he doesn't get a bag of airline peanuts after DJ.
** A midseason trailer for ''Total Drama World Tour'' spoils when Lindsay's elimination happens.
** Trailers for ''All Stars'' not only shows Alejandro out of the robot, but also Lindsay and Jo's elimination.
** Another ''World Tour'' example would be where a promotional flier for the season used to have accidentally given away the final two of the last season. This was especially bad because, at the time, the flier came out when there were about six contestants remaining. It was changed before the season aired, but the information had ''long'' been out by then.
** An Italian trailer for ''Pahkitew Island'' shows Beardo's elimination.
* From an episode preview on ''WesternAnimation/TheTransformers'', "But is this really the end of Optimus Prime? Tune in for tomorrow's exciting episode: "The Return of Optimus Prime".
** However, the ''first'' time that aired, it didn't have the narration. Thankfully, newer DVD releases go without it (though of course the DVD's episode list does let you know that an episode called "The Return of Optimus Prime" is coming up.)
** Not to mention all the trailers for ''the movie'' showing clips of [[spoiler:Optimus Prime getting blown to bits while the Narrator asks, "Does Prime die?!"]]
*** Then the very next question the Narrator asks is: [[spoiler:"Then, who will lead the Autobots?" There's not much need for a new leader unless the old one dies, ya know...]]
** The 20th Anniversary DVD set prominently shows [[spoiler:Hot Rod opening the Matrix]] on the inside cover art. This '''literally happens in the last scene of the film'''. And while all the other chapter titles are deliciously subtle, [[spoiler:"Megatron Transformed"]] might have been playing its hand a bit too much.
* [[http://www.youtube.com/watch?v=DV66QJTtGtQ This trailer]] for ''WesternAnimation/VeggieTales: God Wants Me to Forgive Them?!?!'', shows Junior doing exactly that at the end.
** And the trailer following it for ''Dave and the Giant Pickle'' also spoils that the titular pickle is defeated at the end.
** Along with the trailer for ''Josh and the Big Wall'' stating that "the walls will come tumbling down".
* The Comic Con trailer for the Season 2 opener of ''WesternAnimation/WanderOverYonder'' reveals the plot twist that Lord Dominator is [[spoiler:[[SamusIsAGirl actually a woman]] who talks like a ditzy teen]].
* Promos for the second season premiere of ''WesternAnimation/XMen'' blatantly spoiled that Morph was back from the dead and now evil.