History TrailersAlwaysSpoil / WesternAnimation

* Okay, Creator/DisneyChannel may be the all-time king of this trope. 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.

* Not a trailer, but the original lobby card for the classic WesternAnimation/DaffyDuck short ''WesternAnimation/DuckAmuck'' flat out reveals who the mysterious animator is. It shows WesternAnimation/BugsBunny's hand with a paintbrush tormenting Daffy.

** An italian trailer for ''Pahkitew Island'' shows Beardo's elimination.

** The italian trailer for ''Pahkitew Island'' shows Beardo's elimination.

** A ''Pahkitew Island'' trailer shows Beardo's elimination.

** A trailer for ''Total Drama All Stars'' not only shows Alejandro out of the robot, but also Lindsy and Jo's elimination.

** A trailer for ''Total Drama All Stars'' shows Alejandro out of the robot.

** 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 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]].

** The 20th Anniversary DVD set prominently shows [[spoiler:Hot Rot 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.

* The trailers for the ''MyLittlePonyFriendshipIsMagic'' episode "Magical Mystery Cure" included a clip of Fluttershy saying [[spoiler:"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 [[spoiler:with wings]] was actually sighted months before the episode was even announced, but was dismissed by most as an error from the artists.

* The trailers for the ''MyLittlePonyFriendshipIsMagic'' episode "Magical Mystery Cure" included a clip of Fluttershy saying [[spoiler:"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 [[spoiler:with wings]] was actually sighted months before the episode was even announced, but was dismissed by most as an error from the artists.

* The trailers for the ''MyLittlePonyFriendshipIsMagic'' episode "Magical Mystery Cure" included a clip of Fluttershy saying [[spoiler:"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.
** A sign depicting Twilight Sparkle [[spoiler:with wings]] was actually sighted months before the episode was even announced, but was dismissed by most as an error from the artists.

* The trailers for the ''MyLittlePonyFriendshipIsMagic'' episode "Magical Mystery Cure" included a clip of Fluttershy saying [[spoiler:"You look just like a princess!"]], completely spoiling the game-changing twist that occurs the very end of the episode.

* The theatrical trailer for ''WesternAnimation/RugratsInParis'' had 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]].

* The original trailer for ''[[WesternAnimation/TotalDramaIsland 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.

* Nickelodeon Australia once had a commercial for back-to-back episodes of ''WesternAnimation/TheAdventuresOfJimmyNeutronBoyGenius'' that played this for comedy, with a narrator trying to summarize ''every'' episode in a single breath so the viewers wouldn't have to wait to watch all of them. He outinles about three episodes before becoming exhausted, and instead suggests they just tune in to watch back-to-back episodes.

* A teaser for ''WesternAnimation/ScoobyDooMysteryIncorporated'' clearly depicts [[spoiler:[[BigBad Professor Pericles]]]] going OneWingedAngel.

* Parodied in the ''WesternAnimation/SouthPark'' episode Professor Chaos:

** 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?!"]] WELL GEE KIDS, I DUNNO!
*** Then the very next question they 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...]]

* In an episode of ''WesternAnimation/FamilyGuy'' (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.]]"

* Parodied in ''WesternAnimation/TheSimpsons'' with an old [[ShowWithinAShow Radioactive Man]] film reel. A giant missile heads towards 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 cloud.''

** The trailers for ''WesternAnimation/TheSimpsonsMovie'' show the exchange between Homer, Bart, and the EPA agent near the end of the movie with the "treasure of I'm a weiner" joke. This spoiled the joke of "To be continued" followed by "right now" as the latter takes place before the former in the movie, showing there is more.
** In 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.

* Another one, the ''WesternAnimation/PhineasAndFerb'' 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!"]] ...Yeah, you get the idea.

*** Then there's "Minor Monogram" where the commercials literally only showed the ending where [[spoiler: Vanessa falls for Monty]].
* Not a trailer, but the original lobby card for the classic WesternAnimation/DaffyDuck short, ''WesternAnimation/DuckAmuck'' flat out reveals who the mysterious animator is. It shows Bugs Bunny's hand with a paint brush tormenting Daffy.

* Nickelodeon Australia once had a commercial for back-to-back episodes of ''WesternAnimation/TheAdventuresOfJimmyNeutronBoyGenius'' that played this for comedy, with a narrator trying to summarize EVERY episode in a single breath so the viewers wouldn't have to wait to try and watch all of them. He outinles about three episodes before becoming exhausted, and instead suggests they just tune in to watch back-to-back episodes.

* 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.
* 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 trailer for "Heather Report" in ''WesternAnimation/DragonsRidersOfBerk'' completely reveals that Heather is TheMole working for [[BigBad Alvin]].