Discussing these Western Animation characters gives away that there's more than meets the eye to them.
- Adventure Time:
- Simon Petrikov 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 a man who is over a thousand years old, having lived as a antiquarian prior to The Mushroom War, and was the foster parent of Marceline until her early teens. The magic crown he wore in order to protect himself and her eventually drove him to utter madness, turning him into the Ice King and making him unable to remember his life as Simon. 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 Word of God trivia instead of something important to the show's developing Myth Arc, 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 behave the way they do.
- Betty Grof, Simon's fiancée. Simon believed she was so scared by his behavior when he first put on the crown that she abandoned him, and ultimately died during the Mushroom War. You can leave at that, but you'd be loathe not to mention that her disappearance was actually her entering a time portal to be with Simon in present-day Ooo. All her future appearances and characterization from the episode "Betty" onward revolve around her attempts to reverse the effects of the crown or prevent the Mushroom War from occurring in the first place.
- Shoko is a somewhat minor character, but to even mention her means you have to bring up that she's Finn in a past life.
- Minerva Campbell, aka Finn's mother.
- Archer:
- Holly and Slater's existence spoils ISIS being contracted by the CIA.
- Just saying the name "Abijean Kane-Archer" spoils that Archer and Lana have a kid.
- It's hard to talk about the Blue Spirit in Avatar: The Last Airbender without spoiling that he's really the Secret Identity of Prince Zuko. Likewise, giving away Yon Rha's identity spoils how he is no longer leader of the Southern Raiders but a pitiful failure living with his mother, which plays a major role when Katara confronts him.
- Michael Korvac in The Avengers: Earth's Mightiest Heroes, since the Avengers don't learn about the murders he committed until relatively late into episode #32.
- An even bigger one is General Ross, who turns out to be the Red Hulk.
- Carmen Sandiego:
- Gray/Crackle. It's hard to talk about him without revealing that V.I.L.E. wiped his memory after he ended up apprehended by Interpol.
- For most of season 1, Shadow-san simply served as a member of the Big Bad Duumvirate who had an unexplained hatred of Carmen during her time with V.I.L.E. Then the season 1 finale revealed that he was actually Good All Along, and his sour attitude towards Carmen was simply an attempt to keep her from throwing her life away by becoming a full member of V.I.L.E. By season 2, he's on Carmen's team.
- Dexter Wolfe; everything about him beyond the fact that he was a former member of V.I.L.E.'s inner circlenote is a huge spoiler.
- Numbuh 74.239 of Codename: Kids Next Door is a member of the KND science team and initially was just another one of the recurring characters of the 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 Galactic Kids Next Door operative all along. Speaking of, there's no way to talk about the G:KND animatic (An attempt to make a sequel/spinoff happen) without revealing that the Galactic Kids Next Door are possibly evil, or that Lizzie is really Numbuh Vine.
- Detentionaire: Lo Ping, whose mere existence reveals the full extent of the Ping family's involvement in The Conspiracy, as well as the source of Lee's immunity to the Prank Song and enhanced abilities.
- In Disenchantment, all we know about Queen Dagmar in the first season that she's Bean's Missing Mom and The Lost Lenore for Zog. In the last two episodes, we discover that she's not dead, just Taken for Granite, and that Zog's search for the Elixir of Life was to revive her. And then we find out that she's been Evil All Along.
- DuckTales (2017):
- Just mentioning that Della Duck is part of the reboot falls under this, as the show's first Story Arc covers her disappearance, and she joins the cast partway through the second season. The tie-in comics also featured prequel stories where she's adventuring with Scrooge and Donald very early on.
- Likewise, you can't talk about Lena without mentioning that she's Magica de Spell's "niece", which gets even worse by the season one finale and learn that she was actually Magica's shadow, before becoming attached to Webby after Magica loses her powers.
- Magica De Spell herself could be counted as one. While now powerless, seeing her at all would tell anyone that Lena got the #1 dime at least long enough for Magica to be freed from her shadowy prison.
- As a result of being tied to the above-mentioned Della, all of the Lunarians qualify as this, as it's difficult to talk about them without revealing that Della got trapped on the Moon for ten years. This especially applies to General Lunaris, the Big Bad of season 2, as the fact that he was evil wasn't revealed until his second appearance.
- As of "The Duck Knight Returns", saying anything about Jim Starling besides the fact he played Darkwing Duck in a Show Within a Show spoils that he's actually the series' version of Negaduck. Likewise, it's also difficult to talk about the actor who took over the role from him without revealing that he's a) Drake Mallard and b) planning on becoming a "real life" version of Darkwing.
- Any F.O.W.L. operative outside of Black Heron is this, as the majority of them are only revealed to be F.O.W.L. operatives in a Wham Shot in the last seconds of the season 2 finale.
- Webby’s general characteristics and personality is not one, but much of her backstory is shrouded in mystery, and her mysterious backstory is revealed in the finale, making her this.
- Two characters from the finale, May and June, given they have their backstories tied to Webby, her adoptive family, and F.O.W.L.
- Ed, Edd n Eddy has Eddy's brother. He is made out to be The Ace by Eddy, but when he actually appears in Ed, Edd n Eddy's Big Picture Show, it turns out that couldn't be farther from the truth.
- Although they are now a case of It Was His Sled and major Fanfic Fuel, Tommy and Tammy Turner, who appeared in the Distant Finale to The Fairly OddParents!'s Channel Chasers 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 (though the live-action TV movies that came much later retconned this).
- Family Guy has Vinnie Griffin, spoiling Brian Griffin being (briefly) killed off.
- Gravity Falls:
- Bill Cipher. He's what all of the Eye of Providence symbols hidden throughout the show's first season were leading up to. 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 Big Bad in the final season.
- Fiddleford Hadron McGucket was a brilliant scientist and assistant to the Author of the journals that chronicled the bizarre happenings of the town. He became racked with guilt over his knowledge of the journals' secrets and created a device that erases selective memories, and quickly began to overuse it to the point where he lost most of his memories and sanity, turning him into "local kook" and Mad Scientist Old Man McGucket.
- The Author of the Journals. 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.
- Green Lantern: The Animated Series: Aya is this for almost the entire second half of the series. She sacrifices herself to save Razer, comes back, gets dumped, destroys the Anti-Monitor, does a Face–Heel Turn and becomes the Big Bad, tries to go back in time to alter creation, and then, after all of that, she sacrifices herself again to save the universe. Good freaking god.
- Harvey Beaks has the main character's sister Michelle, who spent most of the first season as an egg.
- Hazbin Hotel: Vaggie is Charlie's devoted girlfriend, but to discuss her character to any real degree beyond that role — including how she and Charlie even met — means delving into the reveal that she's really a Fallen Angel and a former high-ranking member of the execution squad.
- Infinity Train:
- The big reveal of Book 1 is that "the Conductor" is actually a usurper named Amelia, motivated by the death of her fiancé, Aldrick. The actual conductor is One-One, the little robot that acted as Tulip's companion throughout the season. It's very hard to talk about either of them without revealing that.
- In Book 4, Kez repeatedly mentions her roommate, Morgan, showing a picture of a man posing outside of a castle. In the ninth episode. we learn that Morgan is the castle, and that the man is Jeremy, who left the Train after getting over his mother and sister's deaths.
- Invincible (2021) has Omni-Man's role as the Big Bad. Those familiar with the comic (or internet memes after the show was released) knew it was coming, but it is almost impossible to talk about the character, or a LOT of the show's inherent premise, without revealing the fact that Mark's father is a ruthless killer.
- The Legend of Korra:
- Hiroshi Sato, whose part in the Mid-Season Twist, specifically him being Evil All Along turns his entire characterization on its ear.
- Everything about Amon is a spoiler, especially him really being Noatak, one of Yakone's children.
- Season Two has Unalaq, whose evilness was sort of obvious, but not to the extent of how far-reaching it was. But it also has Varrick, whose Mid-Season Twist came out of virtually nowhere.
- Kipo and the Age of Wonderbeasts has Dr. Emilia. To discuss her means delving into the backstories of Scarlemagne, Lio, and Song, due to her being an antagonistic presence for all those characters that inspired their motivations. Those being Scarlemagne's hatred of humans as a result of being a poorly-treated lab animal under her control, and Lio and Song's need to keep their research and findings secret from her to prevent her from destroying mutes.
- Miraculous Ladybug:
- Nooroo and Wayzz, whose very existence reveals that there are active Miraculous users besides Marinette and Adrien.
- The Collector is difficult to discuss without revealing that he's actually Hawk Moth. Furthermore, his identity as Gabriel Agreste was leaked ahead of time, but his identity as Hawk Moth wasn't.
- The future Hawk Moth mentioned in "Timetagger", whose existence is a major reveal in that episode.
- Gimmi's very existence spoils the outcome of the season 5 finale.
- My Little Pony: Friendship Is Magic
- Changelings. Their very first appearance in the series was a spoiler, as even promotional material for the Season 2 finale made the episode seem to be about wedding hijinks at worse and clone shenanigans at best.
- You can't talk about Discord without revealing he goes through a Heel–Face Revolving Door before earnestly redeeming himself.
- Diamond Tiara's abusive mother, introduced in "Crusaders of the Lost Mark", is impossible to discuss without revealing that she's the reason Diamond is The Bully she is, Diamond's redemption, and how it leads the Cutie Mark Crusaders to receive their cutie marks. Naturally, the Cutie Mark Crusaders themselves serve as this after the episode as well.
- The entire Changeling species undergoing a Heel–Race Turn in the Season 6 finale, physically changing their appearance in the process. Thorax is a natural extension of this, as he's the Token Heroic Orc who helped caused the change to begin with.
- Starlight Glimmer. Talking about the character after Season 5 is impossible without revealing that she pulled a Heel–Face Turn at the end of it and became the seventh ranger to the Mane Six.
- To know of Sunburst's existence is to know of Starlight's Freudian Excuse for why she became evil.
- Princess Flurry Heart. Yes, ponies can be born as alicorns and Twilight is now an aunt.
- Cozy Glow, the seemingly innocent student at the School of Friendship, is the main villain of Season 8, gathering info on her studies so she can use it to take over Equestria and drain all magic.
- Grogar, the legendary villain of the final season, is Discord in disguise, having brought the Mane Six's past foes together in an attempt to test Twilight on her bravery prior to her coronation as the new ruler.
- My Little Pony: Make Your Mark: Opaline, who is revealed at the end of the special and plays a major role as the Big Bad in the series proper. It's impossible talk about her without discussing that she's an alicorn from the Friendship is Magic era and is the key player in the Happy Ending Override between G4 and G5.
- OK K.O.! Let's Be Heroes has Laserblast, Professor Venomous, and Shadowy Figure. As of season 3, it's impossible to talk about any of them without revealing that they're all the same person, as well as K.O.'s father.
- Over the Garden Wall:
- The protagonists spend about half of the miniseries trying to find Adelaide of the Pasture, Good Woman of the Woods. It's hard to say much else about her without revealing that she's actually a Wicked Witch who immediately tries to brainwash them into being her slaves.
- Auntie Whispers, Adelaide's sister and exact opposite, seems like a fairy-tale style Wicked Witch, but is actually Good All Along (if still creepy).
- Jason Funderburker and Sara, Wirt's rival and crush respectively, are referenced several times before they actually appear in an extended flashback in the penultimate episode, which also reveals that they, along with Wirt and Greg, are normal kids from a contemporary setting that's not part of the show's Anachronism Stew. In particular, it's hard to discuss Jason without revealing that, despite Wirt's characterization of him as The Ace, he's a small, nerdy kid with a bad haircut in whom Sara is completely uninterested.
- Pinky and the Brain: In the Animaniacs (2020) revival, it's difficult to talk about Julia after her first appearance without confirming that Brain causes her to undergo a Face–Heel Turn and become his new Arch-Nemesis.
- ReBoot: Just seeing Matrix makes it obvious that something traumatic happens to Enzo.
- Rick and Morty
- Tammy ends up a walking spoiler, as during Bird Person's wedding she's revealed to be an undercover agent for the Galactic Federation, kills Bird Person, then resurrects him and leads the remnants of the Galactic Federation.
- It's hard to talk about Evil Morty without spoiling that he was the one behind the abduction of various Mortys instead of Evil Rick, who's revealed to be a robot built by him. He also gets elected as the president of the Citadel of Ricks in season three.
- Mr. Poopybutthole becomes a walking spoiler after Beth discovers that he was not a parasite after all.
- Rise of the Teenage Mutant Ninja Turtles: Until "The Evil League of Mutants" and "Shadow of Evil", it seemed Lou Jitsu was only a film star that the Turtles and Splinter were merely fans of. The former episode revealed that he was a pre-mutated Splinter and the latter revealed that "Lou Jitsu" was merely a stage name and like his 1987 and 2012 incarnations, he's a combination of Spared by the Adaptation and Composite Character as he's a still-living and mutated Hamato Yoshi.
- Roswell Conspiracies: Aliens, Myths and Legends: Riniker's true identity.
- In She-Ra and the Princesses of Power, it's nearly impossible to discuss Horde Prime or his army of clones without revealing that Hordak is one of his clones, and a rogue drone to boot.
- Mayor Jones, Angel Dynamite, Mr. E and the Chileses in Scooby-Doo! Mystery Incorporated. Even knowing that most of the tropes around these characters are spoilers probably counts as a spoiler! (Well, except Mr. E, who's clearly hiding something from the beginning.) There's also the simple existence of the Greater-Scope Villain, who turns things inside out and upside down by their mere presence.
- Star vs. the Forces of Evil:
- For a character who literally appears out of nowhere midway through Season 1, Toffee has a lot of hidden secrets regarding his distinctive appearance, his goals, and his past, most of which (especially past Season 1) are very difficult to explain without spoiling someone.
- In Season 2's "Into The Wand", we're introduced to one of Star's ancestors; Queen Eclipsa, a Lady of Black Magic 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.
- Star Wars: The Clone Wars
- The fact that Darth Maul appears at all is a massive spoiler.
- To a lesser extent, General Pong Krell being a traitor.
- Star Wars Rebels
- The fact that Ahsoka Tano, who first appeared in The Clone Wars, appears at all is a massive spoiler. Her return late in season 4 after being missing since the end of season 2 brings with it many more spoilers.
- During the Time Skip between his last season 2 appearance and the beginning of season 3 (at least eight months), recurring antagonist Agent Kallus goes through a Heel–Face Turn and becomes a Rebel spy, one of the Fulcrum agents. In the second half of season 3, he gets found out by his boss, and in the season finale "Zero Hour" ends up escaping and formally joining up with the rebels, fulfilling his role as an Anti-Hero. It's near-impossible to talk about him in season 3, and outright impossible in season 4, without giving this away. Pictures of him from season 4, with his Good Costume Switch, also spoil this.
- Steven Universe:
- Lapis Lazuli and her introductory episodes "Mirror Gem" and "Ocean Gem" revealed that the Crystal Gems are not the Last of Their Kind, and that they are an intergalactic race where the majority of members aren't fond of Earth at all. Talking about Lapis means spoiling the twist that much of the series is predicated on.
- Trying to say anything about Garnet will quickly lead to mentioning that she's composed of Ruby and Sapphire, and vice versa.
- Bismuth has a major role in Lapis' backstory, and delving into her character in any depth reveals that she's a Knight Templar and the antagonist of her episode. Her return brought even more spoilers.
- Pink Diamond's mere existence is somewhat of a spoiler, to the point where the first mention of her name was a Wham Line. Her character in general and what became of her is a mega spoiler that greatly re-contextualizes the backstories of multiple characters and many events.
- 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) though? Up there with Pink Diamond as the biggest spoilers of all.
- Pink Diamond's Pearl was first brought up in Steven's trial for Pink Diamond's shattering, and her connections and role in the event are a source of major questions about what actually happened. What really happened to her and where she is now is directly connected to Pink Diamond's true fate, which is major spoiler territory, as previously stated.
- White Diamond, the reclusive fourth member of the Diamond Authority, wasn't directly mentioned on the show until late in Season 5. Her first appearance in "Legs From Here to Homeworld" has her casually revealing that she knew the truth about Pink Diamond, Rose Quartz, and the Gem War all along.
- Pink Steven's mere existence is this. His formation answers a question fans have pondered for years about Steven's gem half, and with it, proves a major revelation in Rose Quartz's gemstone and her whereabouts after Steven's birth, and said revelation towards Rose also affects Steven and how the audience views him. He also doesn't appear until near the end of the show's 5th and final season note , concluding one of the show's major plotlines.
- The identity of the Kaiju looming over the rest of the season's threats in the opening for Steven Universe: Future is left as a mystery until the second-to-last episode, where it's revealed to be both the show's Final Boss and Steven himself.
- Jonathan Rook in Stretch Armstrong and the Flex Fighters. The revelation that he is Stretch Monster not only turns him from a benevolent benefactor into the Big Bad of the series, but it also places his actions throughout the first season in a sinister new light. The reveal also changes the show's status quo radically.
- Pumyra is this in Thunder Cats 2011 due to being The Mole/Evil All Along.
- Mal from Total Drama All-Stars, Mike's latest revealed personality over a season after the others and the Big Bad for that same season.
- Transformers:
- Transformers: Prime
- Breakdown, whose death and implied rebirth as Silas' new body have seemingly caused Hasbro to delay and deny the existence of his toy. (Though, that's also for budget reasons. The mold was created by Takara to use at their $65 USD pricepoint, rendering it in "financial no-man's land" compared to Hasbro's $22 USD price point for the same figure-class.)
- Unicron. It's a little hard to talk about him without revealing that in this continuity, Earth formed around him.
- Shockwave in Transformers: Animated, right down to him being Shockwave, as he was undercover as the Autobot Longarm.
- In Beast Wars, 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 Heroic Sacrifice of the original Dinobot, as well as how the finale plays out.
- Transformers: Prime
- The Venture Bros. has the Blue Morpho. He's not brought up by name at all until season 6, when the Monarch discovers his lair underneath his condemned family home, but his existence puts a lot of the show's historical events in a different light. Not only is he the Monarch's father, he was a member of the original Team Venture who Jonas Venture constantly mistreated, up to and including having him salvaged from the plane crash that killed his wife and making him into a helper robot for the Ventures as "Venturion". And if that wasn't enough, despite Kano putting Venturion out of commission for nearly killing a young Rusty, he was later salvaged again by Dr. Z, becoming the villain and eventual Guild councilman Vendata, who may have been the one to ultimately have Jonas Thrown Out the Airlock of Gargantua-1.
- Flopin and Elely from Wakfu. They're Sadlygrove and Evangelyne's children, which spoil the fact that Sadlygrove comes Back from the Dead in Season 2, his relationship with Evangelyne continues and surpasses all the roadblocks it faces, and that Evangelyne will become pregnant sometime before the end of that season.
- Season 2 of Wander over Yonder introduces Knight of Cerebus Lord Dominator as a Darker and Edgier version of Ineffectual Sympathetic Villain Lord Hater. Good luck getting to the Season 2 premiere without prior awareness of the episode's final reveal that she's a girl in a towering suit of masculine-looking armor.
- Arsenal in Young Justice (2010): it's very hard to describe him in any detail or even reveal his real name without giving away something about Red Arrow's Tomato in the Mirror twist from season 1.
