"We aim to confound your expectations."
— Adam Muto, executive producer
What time is it? Time to blow your mind.
The original series
- "Mortal Folly" was the first truly serious episode of the series. It featured the Lich, a villain bent on killing everything in Ooo, and/or the world. The battle with the Lich lead to numerous future plotlines and episodes, containing a great deal of inter-episode continuity and a lot of character development, including a falling out between Finn and Princess Bubblegum.
- At the time, "Mortal Recoil" was a major wham episode, as Princess Bubblegum was reverted to thirteen years old.
- "Too Young," the sequel to the "Mortal Folly/Recoil" 2-parter, was a Wham Episode, because it led to the princess turning eighteen again, the first instance of the Finn+Bubblegum romance being squashed. It also introduced Lemongrab, who is the show's biggest example of Princess Bubblegum's harmful, scientifically unethical side.
- "Holly Jolly Secrets Part II". After 20 minutes of Finn and Jake watching the Ice King's awkward and goofy video diary, we're suddenly thrown into an Apocalyptic Log chronicling the creation of the Ice King: He was originally an actual human professor, Simon Petrikov, from before the Great Mushroom War who slowly fell into insanity after buying a strange crown from a Scandinavian merchant, causing him to lose his fiancée Betty in the process. The crown gradually turns him into a blue freak with magic abilities, thus he survives the Great Mushroom War and ends up the thing he is today. He doesn't want to hurt anyone; he just wants Betty (who he called "his princess"). Though he alluded to remembering his past, by "I Remember You", Ice King doesn't even remember it when he's told about it. This gets referenced repeatedly throughout the rest of the series.
- "In Your Footsteps" was a Wham Episode when it first came out, definitely. The episode starts off heartwarming and pretty silly, then it's revealed that the Lich has the Enchiridion.
- "Incendium", of course, scuttled the whole FinnxBubblegum idea with the introduction of Flame Princess.
- In "Burning Low", Princess Bubblegum reveals why she had Flame Princess trapped in the lamp: because if her elemental matrix were to be subjected to too much romance, she may well destroy the earth. This almost comes true, but it's apparently subverted at present by Finn and Flame Princess simply not kissing (directly).
- In "Lady & Peebles", Lady Rainicorn reveals to Jake that she is pregnant.
- Subverted in the follow-up "Jake the Dad", wherein she gives birth, but their offspring are old enough to take care of themselves; thus, he wasn't able to be a father for very long, preserving the "boy and his dog" show dynamic. Many fans expected the children would be a major part of the show from then onward. "We aim to confound your expectations" indeed. Though they return in later episodes.
- "I Remember You" was indeed one. Marceline knows Ice King and knows what he's gone through. She tries to make him realize how tortured of a past he has and gets frustrated and eventually tears up over it. It's also revealed that Marceline received Hambo, her greatest treasure, from him. It's also revealed in a Freeze-Frame Bonus that Ice King discovered the Enchiridion. There was a newspaper headline that said, "Simon Petrikov Unearths Ancient Treasure."
- "The Lich" was the show's fourth season finale. All of the gems on the princesses' crowns? They're magical artifacts that not only protect themselves from the Lich, but also fit into secret holes in the Enchiridion, found by turning the little sword on the book. Oh, and about the Enchiridion? That book that Finn uses to sit on wet grass? It's actually an extremely powerful artifact that allows the user to warp between different dimensions. Booko explains that there exists a multiverse in which universes are randomly connected with naturally occurring worm holes or artificial worm holes created by a powerful artifact—like the Enchiridion. At the end of the episode, the Lich (who was disguised as Billy, and was later confirmed to have killed him and taken his skin) tricks Finn into opening an artificial worm hole into another universe by destroying the book. After the boys enter the worm hole, the last scene shows Finn as a farm boy, and a normal dog named Jake, being called over Finn's human mother. This episode then leads into two additional episodes, making it a three-parter (with an inter-season cliffhanger) with "Finn the Human" and "Jake the Dog", which also call back to all the previous episodes involving the Lich King, as well as the Ice King and Marceline's background.
- The storyboards for The Lich contain a twist that didn't make it into the final episode: the Enchiridion reveals that Finn's biological father is alive and wrongfully imprisoned inside an alternate dimension with all of the multiverse's most evil criminals, where he has apparently taken up kicking everyone's ass. Oh and Finn never knew that he was adopted. And Jake never told him. Yeah. Parts of this scrapped scene were reused for the season five finale and season six premiere.
- "Be More" is a Wham Episode because we finally get to see BMO's family, and we finally get to see Finn meeting another human. To be exact, human turned Cyborg since he predates the Mushroom War. This human also happens to be BMO's creator.
- "Sky Witch": Marceline finally get Hambo back after trying to track the witch for so long, though only because Bubblegum sacrificed the homemade t-shirt Marceline made for her to trade for it. What's more said sky witch, Maja, plans to use the t-shirt in a spell since it contains much more personal attachment then Hambo did. For what though, we'll have to wait and see. The only clue we get is that it'll be "something big".
- "Frost and Fire" is a Wham Episode as, after a long, awesome battle between Flame Princess and Ice King, it ends with The Ice Kingdom destroyed and Flame Princess breaking up with Finn because he seriously hurt her feelings.
- "Too Old" is a Wham Episode because Lemongrab backslides into full-blown villainy and eats his brother alive. Not to mention the episode being filled with several scenes of graphic child abuse and domestic abuse, all played for straight-up horror and tear jerkers.
- And as for fans of the Finn x Bubblegum pairing, the bottom of the ocean where that ship sank in "Too Young" and crumbled in "Incendium" pulls the wreck even deeper into the abyss.
- Rounding out this row of consecutive Wham Episodes is "Earth and Water", in which we learn the real reason Flame Princess was locked up for most of her life (which involved her own father trying to have her tossed in the woods to die) and Flame Princess and Cinamon Bun stage a coup in the fire kingdom and trap Flame King in the prison he kept FP in, with Flame Princess becoming the ruler of Fire Kingdom. Finn and Flame Princess patch things up and while they aren't quite back together yet, it seems they're on the way to repairing their relationship.
- "The Vault" sees the return of the Green Lady (real name Shoko), who was a friend of Princess Bubblegum and witnessed the rise of the Candy Kingdom. Did we mention she was a past life of Finn, who lives in the tree that Shoko died next to? It all works out. No wonder Jesse Moynihan (storyboard artist/writer for this episode) was expecting a big response from this episode.
- The Bath House Gang's headquarters is identical to the mansion from "The Creeps," (where the Green Lady first appeared) and also identical to the Destiny Gang's hideout from "Finn the Human." In other words, Jake was almost right when he said Finn was imagining the Green Lady's appearance in "The Creeps". Finn was actually having a distorted vision from his past life.
- Although it's been pretty much confirmed already through hints and clues, this is the first time it's been outright stated/demonstrated that Princess Bubblegum is centuries older than her physical age. They even revealed it all dramatically with PB taking off her hood at the beginning of the flashback.
- The amulet will probably show up again.
- At the end of "Play Date" Keeoth (the demon whose blood Joshua used to create the demon-blood sword) returns when Ice King reads demonic runes on the sword. When Finn and Jake show up, Keeoth still thinks Jake is Joshua and demands that he return his blood to him. Finn and Jake try to chant the magic words to banish him, Keeoth threatens to kill Ice King and Abracadaniel. Finn has no choice but to destroy the demon-blood sword, returning Keeoth's blood. After Keeoth promises to leave, "I Lied" comes into effect and Keeoth grabs Jake and disappears, ending the episode.Finn: ...Jake?
- "James": Finn, Jake and the titular James (a goofy candy person) join Princess Bubblegum on an expedition when they are attacked by goop zombies. When all escape attempts have failed, James sacrifices himself to save the others. The episode ends with Bubblegum cloning another James. But meanwhile, the original James, now a zombie, crawls out of the pit, followed by more zombies. That's one hell of a Cliffhanger.
- Not an actual episode, but Adventure Time: Explore the Dungeon Because I DON'T KNOW! is a game where the final boss is a bubblegum blob monster that is actually Princess Bubblegum's parents, and the princess in question is 827 years old. Pen Ward has confirmed this info as a part of the series canon.
- "The Red Throne": Flame King escapes and has his partner, Flame Lord, drug Flame Princess and force her to marry him. While Flame King is once again imprisoned, any chance for the Finn/Flame Princess ship is utterly dashed into pieces by Cinnamon Bun of all people, who admits his feelings for her. Of course, it was confirmed to be platonic by the AT crew due to the obvious age difference and the crew not wanting to create Squick.
- Cinnamon Bun also becomes fully baked (it was previously mentioned he was only half-baked), and now displays much more intelligence and capability than ever before.
- "Betty": The release of an Anti-Magic being causes the Ice King's crown to lose it's magic, turning the Ice King back into Simon. Without the Crown's magic, Simon begins dying. He asks Marceline, Finn, and Jake to help him say goodbye to his fiancée Betty. With the sacrifice of Hambo, Simon opens a Portal to the Past...but Betty isn't content to say goodbye and jumps through the portal into present day Ooo. Betty then defeats the Anti-Magic being, which restores Simon's life and powers but also turns him back into the Ice King. Betty endeavors to find a cure for Simon's curse and begins wandering Ooo.
- "Lemonhope": Lemonhope defeats Lemongrab, but instead of staying in the castle to help take care of the Lemon family, he just... leaves, and says he'll be back in a thousand years or so. Flashforward to Lemonhope wandering in the post-apocalyptic remains of... the Candy Kingdom. With technology advanced to exactly where it was when the Mushroom War destroyed human civilization.
- "Billy's Bucket List": Finn gets over his fear of the ocean to honor Billy's bucket list wish of floating in the ocean. By doing so he sees a vision of Billy in the stars, like Mufasa from The Lion King who tells him that his human father is alive in the Citadel.
- "Wake Up": Prismo is killed by the Lich, who is transported with Finn & Jake to the Citadel, revealed to be a prison for beings who have committed crimes on a cosmic level.
- "Escape from the Citadel": The Lich destroys the Citadel and its Guardians and the five surviving inmates escape along with Finn's dad, who abandoned Finn again. Finn defeats the Lich by throwing the Citadel Guardian's healing blood on him, reducing him to a harmless infant. Finally, Finn loses his right arm, following two seasons of foreshadowing.
- "The Tower": Although he fails to build a high enough tower to space, Finn gets a glimpse of that portal from the Citadel, which implies that Martin and his alien crew went in the direction of Earth.
- "Breezy": After learning that his flower arm is dying, Finn tries to get back in the dating game with a bee named Breezy helping him (because she's in love with his flower arm). At the end, Breezy somehow manages to regenerate Finn's original arm.
- "Something Big": Maja the sky witch returns with an immensely powerful being named Darren, possibly the biggest threat to Ooo since the Lich. It takes Finn and Jake arriving with the Ancient Psychic Tandem War Elephant to bring him down. The battle leaves Root Beer Guy dead (killed offscreen by the start of the episode) and Maja in a coma. Finn sets the elephant free, and it wanders the land until it finds Maja, deciding to nurse her back to health while guiding her moral compass. The fact that the episode was based on the beginning of a scrapped Adventure Time movie should tell you something.
- "Joshua and Margaret Investigations": We learn that Jake was born not from Margaret's womb, but from a weird egg that sprouted from his father's head after he got bitten by a shape-shifting monster, which makes him a half-monster hybrid. This also explains how he got his stretchy powers.
- "Is That You?": Jake appears to be stuck reliving past events. Turns out an alternate version of Prismo has pulled him into his dimension in an elaborate scheme to resurrect himself. Following Prismo's instructions, Finn and Jake create and disrupt a time loop, leaving an alternate Jake to sleep forever as Prismo's new host body, an alternate Finn turned into a sword, and Prismo alive and well.
- "The Cooler": This episode marks a turning point for Princess Bubblegum — she goes too far in her Well-Intentioned Extremist tendencies, gets called out for it, appears to reflect seriously on this, and decides to turn off all her surveillance cameras and take a more laissez faire approach to things.
- "Evergreen" reveals to us the whole story behind the Ice King's crown. It was created by Urgence Evergreen, an ice elemental who lived in the dinosaur times. The crown, which grants its first wearer's wish, was supposed to be used to destroy a comet that was set to extinguish all life. However, Gunther (Evergreen's servant) was the one who put it on, and his deepest desire was not to save the world, but to become more like his master, which explains why it grants ice powers, and why those who wear it call their pets "Gunther". To top things off, we see that another comet is once again headed for Ooo.
- "Astral Plane" ends with Grob Gob Glob Grod sacrificing himself to divert the comet we saw at the end of "Evergreen"... and it turns out that this "comet" is actually a spaceship piloted by Martin!
- In "Dark Purple", we finally learn the truth about Susan Strong: she's NOT a fish-person! But she has a strange implant on her head, suggesting she may actually be a cyborg.
- In Graybles 1000+ it moves on from just being 'filler' short sketches to being an actual story, with Cuber running for his life and revealing a proper (if short) backstory for him. Not only that but throughout the episode it is revealed that Finn and Jake are long dead (duh.) BUT Marceline is STILL ALIVE (her house is still there, a little worse for wear, but the lights are still on), Starchy faked his death to escape Princess Bubblegum's tracking beacon she has in all the candy people (possibly around the time of Jake the Brick, meaning that PB cloned him), All the citizens of the Candy Kingdom are still alive and are in stasis inside a giant, futuristic gumball guardian. The Ice Kingdom (now known as the "Ice Crown-dom" in the official storyboard art) is now ruled by a creature called the "Ice Thing", although it's unclear if it's Simon, completely subsumed by the Crown, or if the Crown's powers have been transferred to some other vessel.
- "You Forgot Your Floaties" ends with Betty gaining Magic Man's powers (and his insanity) while Magic Man is turned back into a Muggle.
- "Orgalorg" reveals Gunter's backstory: he was an Eldritch Abomination who was banished to Earth by Glob and turned into a penguin shape. He's also regaining his memories, and this time, Glob is no longer around to stop him when he reawakens...
- As of "Hot Diggity Doom", Princess Bubblegum is no longer the ruler of the Candy Kingdom, her position having been taken by the King of Ooo.
- In "The Comet", Finn gets his grass powers back, and Martin has ascended to a new mode of existence.
- In "Crossover", Prismo tells Finn and Jake that Finn's wish-created world still exists, and that the Lich there is using Ice Prince Finn to get access to the multiverse. Finn and Jake manage to save Farmworld and its inhabitants, Ice Prince Finn rejects the crown and Prismo ensures it's destroyed, and both Finns band together to destroy the Lich... except his hand was sliced off and fell into the multiverse. There is now a piece of the Lich in every single dimension.
- In "I Am a Sword", the Finn Sword get stolen by Bandit Princess and is used for crime. When Finn confronts her, he accidentally impales the Finn Sword with the grass sword, breaking it and leaving Finn comatose. However, part of the grass sword enters the Finn Sword and the episode ends with the Finn Sword emitting a green glow.
- "Normal Man" ends with Normal Man not only making peace with his brother Glob (who survived the events of "Astral Plane") and Tiny Manticore, but also becoming the new King of Mars.
- "Elemental" introduces Patience, the reincarnation of the Ice Elemental, and almost immediately puts her on a path to get revenge on Finn and Jake, who tried to stop her plans. But that's far from the biggest reveal: the big one is that Slime Princess, Princess Bubblegum, and Flame Princess are the new reincarnations of the Slime, Candy, and Flame Elementals respectively.
- The two-part season 7 finale, "Preboot" and "Reboot", hit us with a load of surprises. It is revealed that Tiffany is alive, there is an entire island inhabited by humans, and Susan Strong is a cyborg created to capture stray humans (i.e. Finn) and return them to the island; which she attempts to do after her programming was reactivated. Also, Finn loses his arm again after his grass arm betrays him and possesses the Finn Sword, which results in it becoming a new enemy ready to fight.
- "Two Swords" reveals that the being that showed up at the end of the season 7 finale is a clone of Finn made of grass. How did this happen? After the Finn Sword's gem got pierced by the Grass Sword, a Cthulhu-like being filled the gem with webs made of grass and trapped Finn #1 inside a cocoon. He then tells Finn #1 that he's going to do the talking once he gets out of there. Not only this thing got free, but it's also suffering from a identity crisis, thinking it's the original Finn.
- "Jelly Beans Have Power". Bubblegum finally manages to awaken her elemental powers, but it results in absolute disaster after she saves her own kingdom from a giant Crystal Entity. The episode ends revealing that Patience was responsible for awakening Bubblegum's powers and the Crystal Entity. Not only that, but it's also revealed that she's part of a huge plan involving Patience herself, Slime Princess and Flame Princess.
- "Orb" ends with Finn, Jake and BMO returning to Ooo after the events of Islands... only to find out that something happened to the place while they're away, kickstarting the plot of Elements.
- "Elements" ends with a boatload of loose ends:
- Betty winds up on Mars where Normal Man greets her while holding the Wand of Dispersal that Abe Lincoln was going to use on Jake.
- Sweet P not being affected by the elemental powers aside from his horn getting fixed.
- When Ice King is hit by the World-Healing Wave, the two side gems on his crown fall out.
- The biggest one is at the end when Finn reunites with Jake and it's revealed that Jake now resembles more their Shapeshifting alien parent.
- "Whispers" ends with Fern, being fed up at being a failure, deciding to Kill and Replace Finn.
- It seems that Sweet P destroyed Lich for good. And before that, the Lich referred to himself as " the last scholar of GOLB," further indicating that GOLB is the Greater-Scope Villain of the series.
- "Three Buckets". Fern undergoes a Face–Heel Turn and locks Finn inside a dungeon. Finn manages to escape and goes after Fern, but he accidentally kills Fern in the process. Finn has a Heroic BSoD while Fern's remains are collected by a mysterious man wearing a purple robe.
- "The Wild Hunt" reveals that the monster who attacked the Banana Guards was made by none other than Gumbald, Princess Bubblegum's great uncle and the same man who appeared at the end of "Three Buckets". And the episode ends with Gumbald revealing his next monster that will attack Finn in the future: it's Fern, now fully recovered and with a new look.
- There's more: while they're not officially dating, Finn and Huntress Wizard are now in a casual relationship, with both of them taking it slowly. "Seventeen" reinforces their feelings for each other even further, but as of the Grand Finale, their relationship is left open-ended.
- "Bonnibel Bubblegum" finally shows the origins of the Candy Kingdom, the Candy People and mostly important, Uncle Gumbald's origins.
- Uncle Gumbald isn't really PB's uncle. She made him herself because she wanted a real family.
- Crunchy used to be PB's "cousin" and Manfried was her "aunt" who were transformed by some dumb juice.
- Butterscotch Lake was created by PB to stop her Uncle from building apartment cities —- she wanted him to have fun.
- Mr. Creampuff was created by Gumbald to get Bonnie out of the way.
- Banana Guard 16's story in "The Thin Yellow Line", about Princess Bubblegum quelling the first candy people's uprising by turning them into monsters, turns out to be partially true. The uprising happened, but what they were turned into wasn't monsters (just stupid candy people) and it wasn't PB's fault (one of their own caused it for the others, then accidentally did the same to himself when he tried to use it on her).
- "Seventeen" ends with Gumbald's return being confirmed to the rest of OOO, Finn finding out that Fern is still alive, and Finn turning 17.
- At the end of "The First Investigation" Jake learns that he is the son of a shapeshifter, and said shapeshifter abducts him currently unclear reasons.
- "Jake the Starchild" reveals that Warren Ampersand (Jake's shapeshifter dad) is nothing more than a fraud. He's been implanting eggs on several hosts for years in order to suck the life of his own offsprings to extend his lifespan. And he was going to do the same thing to Jake.
- "Temple of Mars" ends with Betty deciding to summon GOLB in order to save Simon, and she's taking Normal Man with her after telling him that Margles can probably be saved too, judging by his reaction.
- "Gumbaldia" kickstarts the events of the Grand Finale by making Princess Bubblegum declare war against Gumbald after Peppermint Buttler is affected by the dumdum juice that was drenched on Finn and Jake's body by Cousin Chicle, who's been reverted as Crunchy by accident. Not only that, but Gumbald has reunited almost every single foe from the past to fight against the Candy Kingdom alongside Fern: Bandit Princess, Me-Mow, Peacemaster, Samantha, the red squirrel, Sir Slicer, Ricardio, Ash, Scorcher, Pete Sassafras and... the Ice King and Gunter.
- Subverted in the Grand Finale itself, as the war not only ends up being called off, but when GOLB shows up, most of these villains run off in fear.
Distant Lands
- "BMO" has a few reveals: The cause behind the Earth's crater? An explosion caused by a massive amount of energy. Mr. M's identity? Martin Mertens, and it's possible that his partnership with Hugo was the catalyst for his imprisonment at the Crystal Citadel. The ending, however, is a massive shocker: the special is revealed to be a Stealth Prequel to the original show, as the last scene shows BMO meeting Finn and Jake for the first time.
- While "Obsidian" reveals the reason behind Marceline and Bubblegum's break-up and Marceline's abandonment issues caused by her mother's death, the ending of the episode drops a massive bomb: Finn, now as an adult, arrives at the Glass Kingdom with Simon and Bronwyn, but Jake is nowhere to be seen, other than a tattoo in Finn's chest. Not only Bronwyn took Jake's place as Finn's partner, but something happened to him between the finale and "Obsidian".
