Note: This is a Spoilered Rotten trope, that means that EVERY SINGLE EXAMPLE on this list is a spoiler by default and most of them will be unmarked. This is your last warning; only proceed if you really believe you can handle this list.
Times where The Ending Changes Everything in Western Animation.
- The Adventure Time episode "In Your Footsteps" features a strange bear that imitates everything that Finn does in a very uncanny way. Although Jake is suspicious of the bear throughout most of the episode, Finn doesn't mind, until towards the end, when he believes that the bear was using him to get with Princess Bubblegum. When Finn calls him out on this, the bear leaves the party, feeling crushed. Then Finn realizes that the bear was just trying to be like Finn so he could be a hero as well. In a heartwarming moment, Finn gives the bear a copy of the Enchiridion (a hero handbook), telling him that one day, he'll become a great hero. In the last few seconds of the episode, the bear climbs the mountain, where the snail, who is possessed by the Lich, asks him if he got the book. Turns out, the entire episode was all part of the Lich's Evil Plan.
- Adventures in Odyssey: One episode begins with Dylan using the imagination station which starts malfunctioning. After the imagination station is shut down, Dylan goes back in to retrieve his backpack at the same time that Eugene turns the station back on due to mishearing a command from Mr. Whittaker. Dylan goes through a series of adventures in the imagination station but there are signs it is still malfunctioning. All three adventures he goes through strangely feature the same villain who wants to capture him and the same mysterious man who wants to protect him. After the mysterious protector sacrifices himself to defeat the villain, he suddenly reappears alive and reveals that Dylan never reentered in the imagination station, he is actually having a Near-Death Experience after falling off the ladder when the imagination station was turned back on and severely injuring his head. The recurring villain was actually the Grim Reaper, and the guardian implies himself to be an angel. A similar plot also happens in the radio episode this episode was adapted from.
- The Arthur episode "The Boy Who Cried Comet" ended with the characters turning out to be aliens and the revelation that the show was being filmed on another planet.
- The finale of Camp Lazlo reveals that Scoutmaster Lumpus was an asylum escapee who locked the real Scoutmaster (who looks suspiciously like a certain cow who is friends with a certain wallaby) in a closet for the whole summer. The ending definitely came out of left field.
- Parodied in the Clone High episode "Sleep of Faith: La Rue D'Awakening", in which Gandhi realizes that the mysterious trucker who has been mentoring him all episode is a ghost or hallucination. He has a Once More, with Clarity flashback montage of events from the episode... which, among other things, reveals him floating down the highway four feet above the pavement because the truck he was riding in never existed.
- Closed Mondays features an alcoholic carrying a bottle who stumbles around an art exhibition, watching the works of art come to life in various odd and disturbing ways. At the end, he climbs up on a plinth and turns into a sculpture; he is revealed to be one of the works of art as well.
- DuckTales (2017): The series finale reveals that Webby isn't actually Beakley's granddaughter but a Opposite-Sex Clone of Scrooge which gives an entirely new meaning to Webby's personality and her relationships with Scrooge, Beakley, and the triplets.
- Family Guy:
- "Forget-Me-Not" has Peter, Brian, Quagmire and Joe, after a drunken night at the Clam, end up in a car accident. They awaken in hospital with no memory of who they are, in a Quahog where they are the only inhabitants. They use small clues to try and remember small details of their lives, but a misunderstanding leads Brian, Joe and Quagmire to believe that Peter is an alien who caused the "Apocalypse" that wiped everyone else out. Brian, after bonding with Peter, tries to save him, and ends up taking a bullet for Peter. He then wakes up in a machine that Stewie has hooked the four up to, revealing that the post-apocalyptic events were actually a simulation designed to test whether Brian and Peter would ever be friends if Brian wasn't Peter's dog.
- In the "Stewie Kills Lois/Lois Kills Stewie" two-parter, Stewie apparently succeeds in killing Lois by knocking her overboard on a cruise ship. However, she survives, albeit with amnesia, before she remembers what happened and returns home, taking on Stewie in a fight that leaves Stewie dead. Turns out that both episodes were another simulation, this one based around what would be likely to happen if Stewie tried to legitimately kill his mother.
- Over the Garden Wall's penultimate episode reveals that Wirt and Greg are not inhabitants of the fantasy land they've been traveling through, but two ordinary kids from our world currently drowning in a pond. The strange clothes they're wearing are their Halloween costumes.
- Rick and Morty:
- In the episode "Close Rick-Counters of the Rick Kind", Rick C-137 (the story's main Rick) is accused of killing numerous other Ricks in different timelines and kidnapping their Mortys. When he and Morty investigate to find the real killer, they discover that it's an "Evil Rick" who's apparently behind it all. Evil Rick is killed near the end of the episode by dozens of his escaped Morty prisoners; however, when the Rick-police are investigating his body, they discover that a receiver was planted in Evil Rick's brain and he was being controlled remotely by someone else the whole time. The person controlling him? His Morty "sidekick" (dubbed "Evil Morty" by the fandom), who had but two short lines throughout the whole episode, and was hiding the transmitter behind his eyepatch. What's more, he completely gets away with it (to an extent), removing his eyepatch so he can easily blend in with the crowd of other Mortys with no one even knowing that he was the true mastermind.
- In "The Ricklantis Mix-up", the Citadel of Ricks is just beginning to rebuild after Rick C-137 killed the entire Council of Ricks back in the Season 3 premiere "The Rickshank Redemption". They decide to democratically elect a president as their new leader, and while most of the candidates are Ricks, there is one Morty candidate, who manages to easily be the most inspiring and likable of the candidates. At the end of the episode, he's narrowly won the election and is now President Morty. Pretty awesome, right? But then he shows his true colors by having a bunch of his dissenters murdered on the spot, and then The Reveal right before the episode's Fade to Black is that President Morty is actually none other than Evil Morty from the above example, leading the audience to realize just whom they've been rooting for the entire episode.
- The Grand Finale of Samurai Jack does this to the first episode, where the battle concluded with Aku flinging the hero through a time portal into a Bad Future "where my evil is law." Aku said, at the end of that episode, "We will meet again, Samurai, but next time you will not be so fortunate". Well, he was only too right on that first claim, but dead wrong on the second. The events of the Finale cause Jack to return only seconds later with Ashi (Aku's own daughter from said bad future) by his side, and Aku can only shout that "You're back already??" and with Jack having fifty years more experience under his belt due to the difference in time, the villain is quickly crushed, thus finally ending his reign of terror.
- The Simpsons: One episode has Bart and Lisa noticing that there are no pictures of Maggie in their family photo album, leading to a Whole Episode Flashback in which Homer recounts how he was finally able to quit his job at the power plant and take a job he loved, only to be forced to go back to the power plant after Marge gets pregnant with Maggie and they need the higher income. It seems like the whole thing is leading up to the suggestion that the Simpsons don't keep pictures of Maggie because Homer resents her for costing him his chance at a dream job — but then he reveals the conclusion of the story, which is that he instantly loved Maggie from the moment he laid eyes on her. He then explains that the reason there are no pictures of Maggie in the album is because he takes them all to his job, hanging them around his office to cheer him up and remind him of the value that he gains from his work (the ability to support his family), complete with a sign that reads "Do It For Her". In one scene, a story that looked like it was going to be yet another example of Homer's selfish attitude is transformed into one of the series' most heartwarming episodes.
- Steven Universe:
- In the final season, it is revealed that Rose Quartz, the titular character's deceased mother, was actually Pink Diamond in disguise (something that had been foreshadowed since the first season). Pearl was fully aware of this, having been her dedicated Pearl and helping with the deception, but couldn't say anything as not saying anything about it was the final order she was given by her master's Diamond persona. The episode explaining all this completely changes everything viewers thought they knew about Rose and Pearl's characters and their relationship with each other.
- Future, the epilogue miniseries, recontextualizes many of the original series' moments as traumatizing scenarios that contributed to Steven developing PTSD and a Guilt Complex. While the original series would only explicitly touch upon this idea towards its end, Future has this as the crux of his character arc, which places a melancholic underscore to previous seasons and the movie.
