History WalkingSpoiler / WesternAnimation

[[folder: Adventure Time]]

[[folder: My Little Pony]]

* ''WesternAnimation/StarVsTheForcesOfEvil'':
** For a character who literally appears out of nowhere midway through Season 1, Toffee has a ''lot'' of hidden secrets regarding his [[{{Fingore}} distinctive appearance]], his goals, and his past, most of which (especially past Season 1) are very difficult to explan without spoiling someone.
** In Season 2's "Into The Wand", we're introduced to one of Star's ancestors; Queen Eclipsa, a LadyOfBlackMagic who ran off with a monster as her love. Like Toffee, it's hard to reveal more beyond that without giving away big twists, such as her status in Season 3 and history with her descendants.
** Come Season 3 and the episode "Monster Bash", Miss Heinous is firmly in this territory when both her real name and her backstory is revealed.
* Lapis Lazuli from ''WesternAnimation/StevenUniverse'' reveals that the Crystal Gems are not the [[LastOfHisKind Last of Their Kind]], and that there is another faction of gems that does ''not'' care about Earth. Her introductory episodes, ''Mirror Gem'' and ''Ocean Gem'', set the stage for the entire plot to come and reveal a good deal of context behind previous episodes, such as the [[MonsterOfTheWeek Gem Monsters]] being corrupted gems.

** Bismuth has a major role in Lapis's backstory, and delving into her character in any depth reveals that she's a KnightTemplar and the antagonist of her episode.

** Rose Quartz has been a part of the show from the beginning, and it's not a spoiler that she's Steven's mom and the former leader of the Crystal Gems. Any mention of her pre-Greg past (along with Pearl's, since their stories are intertwined) is probably the '''biggest''' spoiler of all, [[spoiler: since she and the above WalkingSpoiler Pink Diamond are the same person]]. It's so spoilery that we can't even show it unspoilered in a page ''about'' spoilers.

* Arsenal in ''WesternAnimation/YoungJustice'': it's very hard to describe him in any detail or even reveal his real name without giving away ''something'' about Red Arrow's TomatoInTheMirror twist from season 1.

* Lapis Lazuli from ''WesternAnimation/StevenUniverse'' reveals that the Crystal Gems are not the [[LastOfHisKind Last of Their Kind]] and that the monsters fought from the beginning are corrupted gems.

** Ruby and Sapphire's mere presence spoils that Garnet is their fusion.

** Rose Quartz became the biggest of all when it was revealed that [[spoiler: she and Pink Diamond are the same person]].

** Simon Petrikov, aka the Ice King, is an interesting case of this, as the character has been in the show since Day One. However, nothing can really be discussed about him without mentioning the season three and four plot twists that completely turn the character and the show's universe on their heads: he's over a thousand years old, having lived as a antiquarian prior to [[WorldWarIII The Mushroom War]], and flashbacks to this era have him referencing real world locations and pop culture. He was the foster parent of Marceline until her early teens, and the magic crown he wore in order to protect himself and her was what drove him [[WithGreatPowerComesGreatInsanity to utter madness]] and made him unable to remember his life as Simon. when she's a little kid, and he reveals that his crown protects him but makes him crazy. Prior to "Holly Jolly Secrets" and "I Remember You", which revealed some of this information, Ice King was played more as a pure joke villain rather than a sympathetic character, Ooo's status as a post-apocalyptic Earth was just WordOfGod trivia instead of something important to the show's developing MythArc, and Marceline's own past was similarly shrouded in mystery. Talking about Simon Petrikov is necessary to explain an important part of the show's lore and why both Marceline and Ice King's behave the way they do.

** Bill Cipher. He's what all of the [[ArcSymbol Eye of Providence symbols]] hidden throughout the show's first season were leading up to, and it's hard to mention him without noting that he's a demon who has history with the Author of the Journals, and that he becomes the show's BigBad in the final season.

** The Author of the Journals himself. While his existence itself isn't a spoiler, his identity as Grunkle Stan's twin brother who had spent the past thirty years stuck traveling the multiverse is.

* ''WesternAnimation/{{Adventure Time}}'':

* ''Franchise/MyLittlePonyEquestriaGirls''
** It's impossible to talk about [[WesternAnimation/MyLittlePonyEquestriaGirls the first film]]'s BigBad Sunset Shimmer without talking about [[TheAtoner her redemption arc]] in the second film, which in turn leads to her becoming TheLeader of the human Elements of Harmony from the third movie onwards.
** You can't talk about Human!Twilight Sparkle without discussing the events of the third movie, with her undergoing a similar AGodIAm transformation that Sunset did in the first film.

** It's impossible to talk about [[WesternAnimation/MyLittlePonyEquestriaGirls the first film]]'s BigBad Sunset Shimmer without talking about [[TheAtoner her redemption arc]] that leads her ultimately becoming TheLeader of the Human Elements of Harmony for the remainder of the series.

[[folder: My Little Pony: Friendship Is Magic]]

** You can't talk about Twilight's castle without explaining that her tree library was destroyed at the end of the fourth season.

** Twilight Sparkle, aka the show's main character, herself. There's no getting around the fact that she became a ''[[RoyalsWhoActuallyDoSomething Princess]]'' who ascended into an [[WingedUnicorn alicorn]] at the end of the third season.

** Simon Petrikov. Nearly everything about him is a spoiler. He's Ice King in the past over 1,000 years ago before the mushroom war, he mentions a real country and references a real show, he takes care of Marceline when she's a little kid, and he reveals that his crown protects him but makes him crazy. Every one of those things is a spoiler because Ice King starts out seeming like an evil villain, everyone calls the planet Ooo, Marceline doesn't seem like she'd associate with Ice King, and these facts explain a lot of Marceline and Ice King's odd behavior which is the main thing that makes them interesting.
** Betty Grof, Simon's fiancée. Simon believed she was so scared by his behaviour as the Ice King began to takeover his personality that Simon never saw her again, and then she died during the Mushroom War. However, her appearance in "Betty", shows that she jumps through a time portal to be with Simon, and is now working to turn Ice King back into Simon for real.
** Shoko. It's hard to talk about her without mentioning that she's Finn in a past life, that she dies at the end of the episode, that she's the ghost Finn saw in The Creeps, that yet another version of Finn (Shoko in this case) had a replacement arm, that Princess Bubblegum and some of her citizens are extremely old, or that Princess Bubblegum made her citizens.
** Minerva Campbell aka Finn's mom.

** Queen Chrysalis and the Changelings. [[OutsideContextProblem Their very appearance is a spoiler]], as promotional material for the season 2 finale made the episode seem to be about wedding hijinks.
** The Changelings ''do'' make an appearance in the advertisements, but only in clips where they have already {{shape shift|ing}}ed into other ponies, giving the impression that the episode will somehow involve mischievous clones (a clone episode wouldn't exist until the following season).
** To a lesser extent, Matilda the donkey from "A Friend in Deed". She shows up near the beginning of the episode apparently just to show how well Pinkie Pie knows her friends and neighbors, then [[ChekhovsGunman she turns out to be very important to resolving the plot of the episode]].
** Twilight Sparkle post-"Magical Mystery Cure" is nearly impossible to discuss without mentioning her becoming a ''[[RoyalsWhoActuallyDoSomething Princess]]''...oh, and [[WingedUnicorn gaining wings.]]
** The Rainbow Friendship Kingdom first appears after the destruction of the Golden Oaks Library.
** [[AbusiveParents Spoiled]] [[RichBitch Rich]], introduced in "Crusaders of the Lost Mark", is impossible to discuss without revealing the CerebusRetcon of the Cutie Mark Crusaders' arc.
** Discussing [[IndividualityIsIllegal Starlight]] [[WellIntentionedExtremist Glimmer]] post-Season 5 is impossible without revealing that she pulled a HeelFaceTurn and became the SixthRanger to the Mane Six.
*** To know of Sunburst's existence is to know of Starlight's FreudianExcuse, hence why the unmarked spoilers.
** Princess Flurry Heart; her being born an alicorn is treated as a WhamShot, but her PowerIncontinence causes the episode's main conflict.
** Thorax after his AwesomeMomentOfCrowning in the sixth season finale.

* Just even ''mentioning'' that Della Duck is part of the ''WesternAnimation/Ducktales2017'' reboot (and in fact that the MythArc revolves around her disappearance) falls under this. Likewise, so much of Lena's characterization is shaped around the last minute spoiler in her debut episode that she's Magica de Spell's niece.

* ''WesternAnimation/FamilyGuy'' has Vinnie Griffin, spoiling Brian Griffin being killed off.

** Bill Cipher. He's what all of the [[ArcSymbol Eye of Providence symbols]] were leading up to, he has had a bit of a history with the Author of the Journals, and his end goal is to cause the apocalypse by flooding Earth's dimension with monsters from the Nightmare Realm and giving himself a powerful physical form. Then he ''successfully'' does this near the end of the series. At least, regionally, as the town itself has a kind of natural barrier keeping him inside, which is the only hope the heroes have against him.

** The Author himself is this to an extent. His existence itself isn't a spoiler but his identity most certainly is. In "Not What He Seems" it's revealed that he's Stan Pines' twin brother.

** In ''WesternAnimation/BeastWars'', Tigerhawk's mere existence lessens some of the tension in season 2, despite not appearing until the tail end of season 3 (also the last season). Similarly, the existence of the Dinobot clone spoils the HeroicSacrifice of the original dinobot, as well as how the finale plays out.

* Numbuh 74.239 of ''WesternAnimation/CodenameKidsNextDoor'' is a member of the KND science team and initially was just another one of the recurring characters of the [[HeroesUnlimited many, many KND operatives.]] He got a big boost of importance in the sixth and final season as part of the unfolding "Splinter Cell" arc, and the viral campaign to get a KND sequel series takes this ''even further'' with the reveal that he was an undercover ''[[AlienAmongUs Galactic]]'' Kids Next Door operative all along.

* Just even ''mentioning'' that Della Duck is part of the ''WesternAnimation/Ducktales2017'' reboot falls under this. Likewise, so much of Lena's characterization is shaped around the last minute spoiler in her debut episode that she's Magica de Spell's niece.

* Although they are now a case of ItWasHisSled and major FanficFuel, Tommy and Tammy Turner, who appeared in the DistantFinale to ''WesternAnimation/TheFairlyOddParents'''s ''WesternAnimation/ChannelChasers'' special, were this, as they show that in 20 years, Timmy would part ways with Cosmo and Wanda, grow up, get married, and have two children who would get Cosmo and Wanda as fairy godparents ([[{{Retcon}} unless you go by the live-action TV movies that came much later that is]]).

** Bill Cipher. He's what all of the [[ArcSymbol Eye of Providence symbols]] were leading up to, he has had a bit of a history with the Author of the Journals, and his end-goal is to cause the apocalypse by flooding Earth's dimension with monsters from the Nightmare Realm and giving himself a powerful physical form. Then he ''successfully'' does this near the end of the series. At least, regionally, as the town itself has a kind of natural barrier keeping him inside, which is the only hope the heroes have against him.

* ''WesternAnimation/MiraculousLadybug]]'' has [[ForcedIntoEvil Nooroo]] and [[TurtlePower Wayzz]], whose very existence reveals that there are active [[TransformationTrinket Miraculous]] users besides [[TheHero Marinette]] and [[TheLancer Adrien]].

** Evil!Morty is this due to the fact that [[TheDogWasTheMastermind he is the one behind the abduction of various Mortys]] instead of Evil!Rick, who's revealed to be a robot built by him.

** To a lesser extent, Matilda the donkey from "A Friend in Deed". She shows up near the beginning of the episode apparently just to show how well Pinkie Pie knows her friends and neighbors, then [[ChekhovsGunman she turns out to be very important to resolving the plot of the episode]]. (The GenreSavvy, however, might realise how important a female donkey would probably be in an episode featuring a ''male'' donkey as a major character.)

[[folder: My Little Pony Friendship Is Magic]]

* ''WesternAnimation/MyLittlePonyFriendshipIsMagic''
** Queen Chrysalis and the Changelings. [[OutsideContextProblem Their very appearance is a spoiler]], as promotional material for the season 2 finale made the episode seem to be about wedding hijinks.
** The Changelings ''do'' make an appearance in the advertisements, but only in clips where they have already {{shape shift|ing}}ed into other ponies, giving the impression that the episode will somehow involve mischievous clones (a clone episode wouldn't exist until the following season).
** To a lesser extent, Matilda the donkey from "A Friend in Deed". She shows up near the beginning of the episode apparently just to show how well Pinkie Pie knows her friends and neighbors, then [[ChekhovsGunman she turns out to be very important to resolving the plot of the episode]]. (The GenreSavvy, however, might realise how important a female donkey would probably be in an episode featuring a ''male'' donkey as a major character.)
** Twilight Sparkle post-"Magical Mystery Cure" is nearly impossible to discuss without mentioning her becoming a ''[[RoyalsWhoActuallyDoSomething Princess]]''...oh, and [[WingedUnicorn gaining wings.]]
** The Rainbow Friendship Kingdom first appears after the destruction of the Golden Oaks Library.
** [[AbusiveParents Spoiled]] [[RichBitch Rich]], introduced in "Crusaders of the Lost Mark", is impossible to discuss without mentioning the CerebusRetcon of the Cutie Mark Crusaders' arc.
** Discussing [[IndividualityIsIllegal Starlight]] [[WellIntentionedExtremist Glimmer]] post-Season 5 is impossible without revealing that she pulled a HeelFaceTurn and became the SixthRanger to the Mane Six.
*** To know of Sunburst's existence is to know of Starlight's FreudianExcuse, hence why the unmarked spoilers.
** Princess Flurry Heart; her being born an alicorn is treated as a WhamShot, but her PowerIncontinence causes the episode's main conflict.
** Thorax after his AwesomeMomentOfCrowning in the sixth season finale.

* Arsenal in ''WesternAnimation/YoungJustice'': it's very hard to describe him in any detail or even reveal his real name without giving away ''something'' about Red Arrow's TomatoInTheMirror twist from season 1.
[[/folder]]