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Nightmare Fuel / Adventure Time

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"Just talked to the creator of Adventure Time, Pendleton Ward (@buenothebear). He said that he'd be happy if the show gave people nightmares."
A tweet by Matt Fowler

What time is it? Not the time to give us nightmares, that's for sure!

Adventure Time was easily one of the darkest shows Cartoon Network have ever come up with in The New '10s. When the series moved into Darker and Edgier territory, some episodes managed to show really disturbing (and somewhat depressing) stuff, even by the standards of a children's show.

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  • The Lich. The infamous Big Bad and Knight of Cerebus of the entire series. There's a very good reason why he provides the page image here. For the horrific details, see the ends of the folders for Seasons 2 and 4, and the beginnings of Season 5 and 6. But be warned, they are absolutely not pleasant to read about.
  • The Complete First Season DVD, which depicts every layer of Finn's head, from his hat, through his hair, muscles, skull and brain... The DVDs for seasons two, four, and five respectively dissect Ice King, Marceline, and Jake in a similar manner.note 
  • The fact that Simon went completely insane and gained treacherous ice powers just by wearing a crown. Wearing it once made him unable to get rid of it in the first place, too.
    • The Complete Second Season DVD adds a little insight into this. Like the example with Finn above, the case and discs dissect the Ice King's head. The second disc shows the crown sitting upon Simon's completely frozen brain.
    • The fact that his final progression to the Ice King happened while effectively raising Marceline-who was a little girl at the time. Simon's ice powers and insanity are terrifying enough, but the fact he has to keep a child safe from monsters is scary on a whole other level.
  • The Official Adventure Time Encyclopaedia, the last chapter, they filled it with as much creepypasta as they possibly could. The Chapter is called "If you read this you will die" for a good reason...
  • In "Explore The Dungeon Because I DON'T KNOW!", it is revealed at the beginning that Princess Bubblegum locks all the criminals of the Candy Kingdom in her dungeon "FOREVER!!!" If you thought her mental state was unnerving before, this seals it.
    • The fact the dungeon has characters that wouldn't really be considered "criminals," more like savage monsters, like giant, oozing tentacles, Hugwolves, deer like the one from season 3, the Demon Cat from "Dungeon" somehow made it down there, plus many more abominations. Imagine being trapped down there until you die with all these things running around. Lemongrab's dungeon from "Hey Ice King, Why'd You Steal Our Garbage?" is looking nicer and nicer isn't it?
      • By this logic, this makes Lemongrab giving people twelve years dungeon, thirty years dungeon, or fifty years dungeon seem downright reasonable. To be fair to PB, they weren't serious offenses to get a million years dungeon.

    Season 1 
  • "Slumber Party Panic", which is about candy people turning into zombies after Princess Bubblegum tries to bring them back from the dead. Its third season sequel is even worse.
  • Ricardio not only threatening to cut out Princess Bubblegum's heart out, then showing a horribly grotesque detailed close-up of his face and having him say "And make out with it" with creepy opera music playing in the background.
    • The scenes of the Ice King with no heart. Sure- he's a jerk and he starts off as a harmless villain in the series, but he didn't deserve to be treated so horribly by Ricardio. He's too much of a woobie. The fact that the Ice King explicitly stated that Ricardio threw him in a dumpster and left him for dead really shows us just how evil Ricardio actually is.
    • One of the worst parts had to be the fact that was that Ricardio was going cut out Princess Bubblegum's heart using broken glass bottles.
  • "When Wedding Bells Thaw" was the only episode where the Ice King is not only evil, but downright diabolical. He doesn't just kidnap a princess, stick her in a cage, and marry her against her will. He actually BRAIN-WASHES a princess and forces her into WANTING to marry him! That poor old lady princess... She was so terrified she was actually crying. And the way she was so angrily protesting as the Ice King lowered her down. . . We all know that the Ice King isn't a bad guy- he's a Jerkass Woobie, but this moment very well could have been his moral event horizon, if he had continued in this direction.
    • It becomes worse when you realize he's been under similar conditions for over 1000 years.
  • Marceline's first appearance in "Evicted!". After Jake tells Finn a scary story about a vampire who used to live in Finn and Jake's Tree House, Finn lies in bed awake, and hears a branch tapping against the glass of his window. Then, a shadowy figure appears, tapping on the window as well. Before Finn can make out the figure, lightning strikes, revealing her Nightmare Face. It becomes Nightmare Retardant once she introduces herself, but still.
    • Marceline transforming into a giant bat and appearing to suck Jake's blood, tossing his shriveled body to the floor like a piece of trash. There's also the fact that she would've killed them both if she didn't consider Finn a Worthy Opponent and become friends.
  • "Freak City". Magic Man. One of the first things he does is magically turn a bird inside out. The worst part about the inside-out bird is that it doesn't die. It flops around on the ground for a little bit and struggles to get away - a true Fate Worse than Death if there ever were one.
    Jake: Think happy thoughts - little cute bees, little babies, tiny tiny bunnies
  • "Tree Trunks" ends with the eponymous character eating the crystal apple resulting in her exploding, with Finn and Jake in shock. The extra clip of Tree Trunks in the crystal isn't a problem; Netflix prints and the My Two Favorite People DVD omit the ending, leaving some to wonder what happened to her.
  • "Dungeon" had plenty.
    • Finn's "guardian angel" is horrific, mainly because the sudden change from cute to scary can catch you off guard. She also says something along the lines of "I'm going to cook you and eat your flesh" before showing off her... disgusting face?
    • Demon cat thing! Sure, his knowledge of "almost everything" was rather great, but something about his voice and composure...
      Cat: "I am going to unzip your skin and wear it like a little coat." Also, "I have approximate knowledge of many things. For instance, I know that I am possibly going to slay you, and munch on your eyeballs."
    • The angry face Princess Bubblegum made at the end.
  • "Ocean of Fear": "Ready for step two?"
    • The whole episode made "exposure therapy" look absolutely hellish.
    • Hell... The artists managed to make the ocean itself look absolutely terrifying!
    • The fact that the Fear Feaster's face is at times reminiscent of Red from NES Godzilla Creepypasta is NOT helpful at all.
    • Finn's Nightmare Face while yelling "NOOOOO!"
  • Princess Bubblegum going a bit Ax-Crazy when she thinks the Duke of Nuts has thrown a bottle at her to make her turn green and bald. She's actually legitimately terrifying with her maniacal raving about what she's going to do to him when she catches him.
    • Worse, she's had it in for the Duke for quite some time for stealing her pudding, and her assumption that he turned her green and bald just gave her a good excuse to exact her revenge.
  • If you thought this show was scary so far, wait until you see the original artwork for the title card of "The Enchiridion". It is absolutely horrific, and comes with a very necessary warning. Hell, it borders on Nausea Fuel!
    • The heart monster in the actual episode.
    • The ghoulish cloaked figure initiating Finn's final trial was pretty freaky, too. Something about his arms...
      Evil Guy: Now, enter my brain world, where I will show you some aspect of yourself that you're not eeeenntireeellyyy awaaaaaarrreee offffff...

    Season 2 
  • Pen Ward warned that "It Came From the Nightosphere" would be filled with this. And rightfully so!
    • Marceline's Dad. A soul-sucking malevolent Eldritch Abomination who shows his innards to other people for fun. His voice is creepy. He sounds like a pretty average, nice man. Definitely not the voice you'd expect from such a character. Also when he turns to the Ice King and although we can't see it that well, his face basically EXPLODES.
      • Perhaps it's the more subtle things that make Marceline's Dad creepy- like the way he walks. His gait is like a mix of a creeping spider and an Uncanny Valley marionette.
      • Word of God states that he pretty much represents Satan in this show.
    • Marceline looked pretty scary whenever she had red eyes and sharp claws.
    • While played for laughs the implications of Gunter bitch slapping and being treated with awe by what amounts to the devil does not bode well
    • After Finn stabs Marceline's Dad in the head after growing to a gigantic size, he nonchalantly glances at the sword, smiles, and widens his mouth as he deflates his entire head, making way for the more Lovecraftian-looking one we've seen behind his throat!
  • In "The Eyes," you can see a tiny, skeletal figure next to Finn and Jake's window, hanging itself.
    • The whole episode is a parody of Edgar Alan Poe's Telltale Heart, including Finn being exhausted enough to let Jake trick him into killing the creepy stalker cow.
  • In "Guardians of Sunshine", the 3D animated versions of the monsters are pretty creepy. Honey Bunny is a hideous dripping Blob Monster, and when Finn tries to sneak up on Sleepy Sam, Sam suddenly lets out a blood-curdling scream that sends Finn flying.
  • Both "Belly Of The Beast" and "The Limit" have their moments:
    • "Belly of The Beast"
      • Just the knowledge that a whole cave's worth of party-happy bears could be swallowed and be completely oblivious to the fact for three whole days, continually partying for those three days without stop for rest, personal need, or food, is pretty unnerving.
      • Cubby's reaction to their father yelling at them for, what he thought, was bothering Finn and Jake with their "nonsense about being inside a monster's stomach". They were obviously frightened for their life.
    • "The Limit":
      • Jake's reaction to being put under peer pressure- it nearly stretched him to oblivion!
      • The snake-genie at the end of the labyrinth. Creepy tone of voice, and way too sadistic for a children's show.
  • The Royal Tart Toter. He's insane, has deranged eyes, foaming at the mouth and everything.
    • The grotesque, cave-dwelling humanoid monsters that attacked Finn and Jake in the same episode. Especially the build-up:
      (Finn and Jake walk into a cave, where it's completely pitch-black and we can only see their eyes. Something can be heard sniffing.)
      Finn: Jake?
      Jake: Yeah?
      Finn: Hey man, did you just like, sniff my butt?
      Finn: Yeah.
      Jake: No.
      Finn: Hmm... Alright.
      (Finn and Jake continue walking, then stop again.)
      Jake: Hey, Finn?
      Finn: Yeah, Jake?
      Jake: Did you just uh, lick me all the way up my arm?
      Finn: No.
      Jake: Hmm... Strange.
      Finn: Jake, let me see those matches.
      (Finn lights a match, revealing themselves to be COMPLETELY SURROUNDED by hissing blind creatures.)
      Finn and Jake: AAAAAAAAAAAAAHHHHH!!!
  • The torture the gnomes put Finn through in "Power Animal".
    • Throughout the series, Finn gives very realistic screams. This episode in particular will make you very uncomfortable with the raw pain in Finn's voice as he struggles to stay alive.
    • The very last line of that episode.
    Jake: Let's go eat Cinnamon Bun.
    • The way the gnomes seem to give off vibes of pedophilia, especially when they make Finn pole dance!
  • In "Her Parents", Lady Rainicorn's parents try to EAT Finn! It doesn't help that Bob Rainicorn is voiced by none other than Henry Rollins... imagine that guy threatening to eat you.
    • At the end of the episode, the Rainicorns and Jake indulge in "soy people" which allegedly tastes just like real human flesh. Jake remarks "Finn, you taste delicious!" after trying some of the ersatz human, which prompts Finn to give it a try... The last shot of the episode is Finn's wide grin as he realises how delicious his own flesh is. Brrr...
      • The very end of the episode has the background music steadily getting louder leading up to, during, and after Finn's eating some of the "soy people" to the point where it's heavily distorted.
  • Much of "Susan Strong". Susan going completely manic, and her gathering up her hyoomans to eat everyone in the Candy Kingdom, (except for red stripe man.)
    • Jake's scary line: "We could rule them like gods! *squints eyes, rubs hands, talks in low, soft voice* Angry gods..." Of course, Jake was kidding, but the way he said that line was insanely creepy.
  • Peppermint Butler in "Death In Bloom".
    "I'd like your flesh."
    "Hehehehehe... Stop bein' silly, Peppermint Butler!"
    • The fact that he knows how to enter the realm of the dead and is good friends with Death himself is more than a little disturbing.
    • Plus the quick scene in the season finale where he brings tea to a Lich-possessed Princess Bubblegum and upon catching sight of her sprouts fangs and hisses like a cat before running away on all fours. What the hell is that guy?
    • Apparently, Peppermint Butler is also a friend of Hunson Abadeer, which is horrifying in of itself. In the background of Return to the Nightosphere is a picture of them playing golf. Keep in mind, the Nightosphere is meant to represent Hell and Hunson is meant to represent the devil.
    • He also gets very nervous in You Made Me when Finn wants to see Peppermint Butler's aura.
    Peppermint Butler: "No, you don't want to see that!"
  • All of the scare chords in "Mystery Train," in addition to the atmosphere in general, the lighting, the creepy conductor, and the horrifying ending.
    • The train falls off an open cliff and lands on a gelatin person. Jake says that this wasn't planned, and he was the one who arranged the train ride for Finn. The ending seems to suggest that Jake knew this the whole time and either he or the designer of the train tracks was planning to commit a mass murder-suicide.
      • Please, didn't you ever think that train was supposed to stop near the end of tracks so that everyone could use some kind of safe way to get down and the joke just got a bit too far? Especially since it would have been able to stop if not for Finn damaging the controls in the fight Nice Job Breaking It, Hero (Almost)
  • Marceline's ghost friends in "Heat Signature" are a little bit terrifying in their Comedic Sociopathy. Marceline tricks Finn and Jake into thinking she's turned them into vampires, and has them do ridiculous things as "vampire training." The ghosts claim that Finn and Jake being kicked repeatedly by them is part of the training, and trick Finn and Jake into throwing themselves off a cliff because they think they can fly.
  • The season 2 finale as a whole. The Lich, who looks as terrifying as expected? Check. Princess Bubblegum hospitalized in serious condition? Check. Her SKIN MELTING OFF HER BODY AS FLAMES DANCE ABOUT HER? Check.
    • Unlike most villains on the show, The Lich is a monster that even Finn and Jake had trouble dealing with.
    • If you look closely you can see very tiny and faintly seen pupils in the Lich's eye sockets, for some reason it's just disturbing.
    • Here's the link. The low voice for Bubblegum actually makes it worse.
    • To top off the two-parter, a Lich-possessed Bubblegum turns into a gigantic Eldritch Abomination and wreaks havoc on the kingdom. Finn asks Ice King to freeze her to buy Finn time to save her, and IK does so. The citizens gather around and rejoice... until the frozen monster tips over and shatters, sending the body into pieces. The entirety of part 2 deserves a place of honor here.
    • During the first showdown with The Lich, Finn shoves his sweater into the Lich's eyes, pulling his skull out and shattering it to pieces. How does the Lich react during all this? He laughs.
    • The Lich is basically the personification of this trope. The dude has no brilliant evil plan or secret weapon: he's just there to KILL EVERYONE.
    • And at the very end of part two, it's shown that the snail is still possessed by the Lich's evil influence... Probably for the sake of cliffhanger, but still...
      • What makes this even worse is that any further appearance of the snail shows that the Lich is silently watching Finn and Jake's every move...
    • The Lich was redrawn as the creators didn't think he was scary enough.
      • Which, essentially, makes it look like The Horned King, an already terrifying character design in its own right, with such lovely additional features like a partially-rotted face with flying skin flaps, empty eye sockets, and large, curved fangs in a constant Slasher Smile
    • But, wait, there's more! He's gifted with extremely talented Mind Rape abilities that let him force unwitting victims, who are not even aware of the fact they are being mentally possessed, to do his bidding, just by looking at them! And he's still able to pull this off in a cryogenic state!

    Season 3 
  • The revelation that those gladiator ghosts in "Morituri Te Salutamus" were originally best friends (or, according to Word of God, gay lovers), just like Finn and Jake, who were driven insane and forced to kill each other.
    • Before that, how the gladiator ghosts would be in visible despair as they fought, either for killing their friend ("Forgive me, Valius!") or for their friend betraying them ("Et tu, Walius?").
    • Also when Finn became insane and tried to KILL JAKE. Granted, he was faking it BUT WE DON'T KNOW THAT!
    • At the end of this episode when the gladiator ghosts are floating up to the heavens with the creepy sounds in the background.
      • According to Andy Ristaino, the gladiator ghosts were LOVERS. Presumably, they lived together, slept together, and loved each other dearly... and they killed each other. The revelation that they were romantic partners in ADDITION to being friends just adds on even more horror, and it's an even bigger tear jerker.
      • The Fight King himself looks like a burned corpse and makes awful cracking noises when he moves.
  • The background music in "Memory of a Memory." It's so eerie...
    • Ash isn't a really scary character himself, but his entire plan to get Marceline back in a relationship with him is downright unsettling. First, he breaks into Marceline's house and casts a sleep spell on her, then goes out of his way to disguise himself as her "spirit animal" to get Finn and Jake to steal the memory of their breakup from her to destroy it. Had Finn not acquired his own memory of the incident while spending time in Marceline's mind, then she would've been stuck in a one-sided relationship with an emotional abuser, and not even realize it!
      • While we don't see it ourselves, Ash sneaking into Marceline's house and casting a sleep spell on her, leaving her unconscious on the floor raises a ton of disturbing implications from Marceline's POV.
  • Scorcher from "Hitman." Unlike most villains in the show, he's quiet, calculated, ruthless, and has no amusing quirks.
    • The title card, which appears to be Finn and Jake being targeted by a sniper.
  • "Too Young" - Princess Bubblegum's flashback of creating Lemongrab. The scene zooms in on PB's dark, creepy laboratory as sinister strings play over the soundtrack. PB looms over a bed/table, where Lemongrab (minus face) is lying. She sticks a nose onto his face, and pours a chemical from a vial onto his face as well. The chemical seeps into his skin, and features form. Lemongrab's eyes snap open, and he lets out a hideous groan. Then, he bolts up and starts flapping his arms, screaming in terror as Princess Bubblegum looks at him with helpless, surprised fright. Then Lemongrab screams louder, as his eyes roll back into his head. Princess Bubblegum's reaction is the same as ours- she gasps in horror and mortification. The scene is terrifying from PB's, and Lemongrab's perspective.
    • There was a very creepy scene storyboarded for "Too Young" that didn't make it into the episode, most likely to save time. Normally, Lemongrab is just an obnoxious, unhinged jerk, but in THIS scene, he's downright terrifying, and doesn't show qualms about terrorizing small children and making them cry. In the scene, Lemongrab says, "Anyone who disagrees or disobeys will be thrown into the dungeon." A little candy CHILD gasps, and asks, "The Royal dungeon?" Lemongrab turns to the kid angrily, and shouts, "Thirty-TWO days in the dungeon for you!" The kid stutters a bit, trying to defend himself... until Lemongrab makes a horribly creepy, deranged Nightmare Face and shouts "DUNGEON!" The kid leaves the room in tears.
    • Lemongrab's laugh. Basically, a totally joyless, insane laugh as his head flails around with weird squishy noises. Even everyone else is creeped out.
    • Lemongrab himself creeped out a significant portion of Adventure Time fans- thanks to his psychologically unstable personality, banshee-like screams, and his Dull Eyes of Unhappiness.
    • The name of Too Young's Sequel Episode: You Made Me! *shudder* Lemongrab watches the candy people while they sleep. *shudder* Creepy!
  • Fionna and Cake. It was a pretty light-hearted episode, but one scene is downright terrifying for adults, especially women, to watch. Prince Gumball says, "Fionna, I have to show you something." He takes Fionna's hand and leads her up to his bedroom. "Hey, is this your bedroom?" Fionna asks. We see Gumball's bed, covered in rose petals, illuminated by an off-screen spotlight. We see Gumball lock the door then step towards Fionna with a serious expression on his face, as he unbuttons his shirt. "Woah... heh heh..." Fionna says nervously. Up until The Reveal, where the audience sees the REAL Prince Gumball frozen to the ceiling, it looks like Gumball's about to RAPE Fionna!
    • Horrifying from Cake's perspective. We see Cake standing in the hallway, listening to what's happening upstairs. We hear a loud thumping, and Fionna crying, "Get off of me!" Cake's terrified reaction sells it. And when she comes back to the room, she sees Fionna's dress completely tattered. She launches herself at Gumball and attacks him, screaming "Don't you touch her!"
    • What about when Fionna realizes what's going on and the Ice Queen reveals herself? Fake!Gumball starts laughing and continues removing his clothes. It gets really creepy when Fake!Gumball's voice gets higher and higher in pitch until it shifts into Ice Queen's genuinely unnerving cackle, all the while the Ice Queen appears to be crawling out of Gumball's chest!
  • "The Creeps," as the first Halloween episode, had its moments. The worst part was probably Cinnamon Bun's splattered remains inside a closet!
    • Or the green, slimy ghost that came out of nowhere! Made all the scarier with the Real After All revelation and the sudden flashback that occurs right before Finn makes himself forget about it.
    • Even though it was just a wax replica, PB melting was creepy.
  • "From Bad to Worse" continues the horror found in "Slumber Party Panic", in which the candy citizens turn into zombies again because Cinnamon Bun ate Princess Bubblegum's candy zombie tissue she was experimenting with and turned himself into a zombie that infected everyone else. Things go downhill when Princess Bubblegum herself gets infected, making her face melt in a horrific way, and then get even worse when it turns out the zombie ailment is not limited to the candy people when one bites Jake.
    • When Jake is bitten, the infection spreads from his hand where he was bit trying to reach the rest of his body. All Jake can do is stretch his arm as much as he can to delay the inevitable, and he eventually transforms into a zombie as well.
    • The appearance of the zombies is extremely unnerving. In general, their coloration is dull and gives off the impression of rotten flesh and their eyes glow a menacing bright green. Individuals include Cinnamon Bun who gets horrific cone teeth, Princess Bubblegum with her melting looks (especially her face), and Jake plus Lady Rainicorn who both turn a sickly grey shade with prominent veins.
    • The part where Lady Rainicorn willingly lets zombie Jake out despite Finn telling her not to. She knows he's a zombie, but chooses to let him out of the shower anyway. It leads to her getting zombified too. At the very least the shower is freed up for Finn and Science to occupy long enough to figure out the antidote, but Lady's action is scary in that she so carelessly risks both herself and Finn's life for no good reason.
  • Lub glubs. The name not sound scary at first, but when you find out what they really are... They look like nothing more than harmless inflatable pool toys, but then we find out that they are actually formless Eldritch Abominations that are covered in teeth. Also it's strongly implied that they killed off the last remaining humans.
  • "No One Can Hear You" is a creepy, creepy, episode that is scarier than either of the official "Halloween" episodes that season. The deserted Candy Kingdom is creepy enough, but there's a silent, never-explained, Outside-Context Problem who is just wrong (the bit where he removes artificial front hooves to reveal human hands is... yuk), some of the most shockingly brutal Family-Unfriendly Violence in the whole of the series, an insane Jake with beetles crawling out of his ears using his stretchy powers to attack Finn, the Candy People stuck in gluey saliva being slowly eaten, and all of this supposedly having been going on for up to six months...
  • "New Frontier". The episode involved Jake having a dream revealing the details of his own death, called a "croak dream," and then trying to make sure the death happens once details from the dream start to appear in real life. He claims he's doing so because You Can't Fight Fate, but as the episode goes on, he starts to come across as downright suicidal. Finn gets a bit suicidal as well. When they're in the lake, Finn refuses to leave Jake's side even though he's drowning, saying he'll stay by his side "forever". That leads to some scary implications. If Jake died, would Finn... choose to follow?
    • When Jake's dream was nearly over, out of nowhere the Cosmic Owl appears and lets out a high-pitched shriek, accompanied by a sudden noise.
  • A great overlap between this and Tear Jerker is found in "Holly Jolly Secrets," when we learn that the Ice King used to be a man named Simon Petrikov, who was engaged and becoming an antiquarian. He was sold what would become his Iconic crown, and put it on his head just as a joke for his fiancé Betty. This small contact with the magical artifact led to a slow descent into madness, quickly making way for a Noodle Incident that caused Betty to leave him. The crown then continued turning him into a monster... turning him into what he is now.
    Simon: I don't know when it'll end... (almost whispering) I'm really scared...
    • The subtle take on a Scare Chord that was used when we first see Simon open the cabinet and show his audience the crown.
    • Simon's voice gradually, and subtly changing, into the Ice King's. The physical transformation was clear, but the vocal change really helped to emphasize how his body AND mind were changing.
    • The implication that either the crown either protected the Ice King from one of the events that started the Mushroom War, or made him do so through his power over ice and frost.
    • The worst part is that Ice King's in denial about once being human. It appears Ice King is too far gone to ever be human again.
    • "Please love me again, Betty!"
      • His entire monologue was one minute and a half of pure, concentrated, psychological horror:
        Simon: Hello. My name is Simon Petrikov. I'm recording this tape so that people will know my story. I was studying to be an antiquarian of ancient artifacts. Now, I've never believed in supernatural stuff myself, just had a fascination with superstitions. But everything changed when I came into contact with this item. After purchasing this crown from an old dock worker in Northern Scandinavia, I brought it home and excitedly showed my fiance, Betty. I jokingly put it on my head just for a laugh or something. And that's when it started... the visions. I fought with them, shouted at them until I realized it wasn't real! It was the crown! I quickly took it off, and saw my fiancee in front of me, looking at me with such contempt! What had I said? What had I done when I wore this crown? All I know is, I never saw Betty again. Since then, I now see the visions always whether or not I wear the crown. They tell me the secrets... the secrets of the ice and snow... that the power of the crown will save me with its frost. I don't know yet what this means. As you can see my skin is beginning to turn blue. My body temperature is lowering in a supernatural rate, to what is now about 30 degrees Celsius. I don't know when it will end. I'm really scared. I know my mind is changing... but I'm already too far gone to know what to do. I want people to know that... if I do things that... if I do things that hurt anyone, please, please forgive me! Just... watch over me until I can find my way out of this labyrinth in my brain and regain my sanity! And then maybe Betty, my princess... maybe you will love me again... Please love me again, Betty!
    • This is made even more terrifying with the implication that the Ice King is so obsessed with princesses because he's trying to get back his 'princess' Betty.
    • The music during the final tape. Watch that scene, and just pay attention to the music. It's positively chilling.
  • All those dead animals lying around in Wildberry Princess's castle with their lifeless open eyes...
  • The freakin' clown nurses from "Another Way", especially the Nightmare Sequence Finn has early in the cartoon.
    • It's that damn Scare Chord that accompanies the Monster Clown image that's scary.
    • Finn's unabashed conquest to have it his way. He mortally injures multiple forest creatures in the process, completely going against his code to help anyone. Eventually he sees the errors of his ways and heals them all..
    • This episode can be summed up as doing its best for you to be afraid of clowns, if you weren't before.
  • In "Ghost Princess", Clarence's death. The soft-e-cheez exploded out of Clarence's body with enough force to completely shatter his sternum. Jake had a very good reason to swear off cheese spread...
  • "Dad's Dungeon" had 2 particular scenes. The first being the fruit witches when they went bad and second being the monster at the end.
    • Especially the Fruit Witches sequence. Finn in Jake are in a surreal room full of abundant fruit, while beautiful women are floating around telling them to take a bite. Jake is smart enough to know it's a trap so he stuffs an apple into one of the women's mouths. Vines protrude out of her mouth and eyes and cover her entire body. The vines then fall apart, leaving behind a huge red apple. The other women turn into demons and ferociously tear apart the apple, and feed the shreds to what looks like miniature lub glubs in their hair, revealing what appears to be BONES. INSIDE A BLOODY APPLE CORE.
    • After the demonic girls are done feeding, they left behind an apple core with a dark suspiciously meaty looking center with bones coming out of it and some visible blood. The girls then chase after Finn and Jake, after seeing what happened to the apple, just imagine what would have happened to our heroes. This one really takes Family-Unfriendly Death to a horrific extreme!
    • And regarding the monster... The first we see of it are its GIANT hands, which grab Finn and Jake's dad between two fingers. It stays mostly in shadow, but we do see those GIANT hands, tentacles, and a diamond eye, and it just keeps laughing...
  • Jake, using stretchy powers, acting out a disturbing scene of Finn strangling him in "Incendium." What a twisted mind he has!
    • Do. NOT. Piss. Off. Flame. Princess. When Jake says "Never mind" to Flame Princess and (acting as Finn) suddenly and rudely rejects her, she says "You... WHAAAT?!" while abruptly changing into her fiery form.
    • Finn raging after Flame Princess burns his pictures of PB, and screaming at her. "WHO LIT THAT FIRE?! I'LL KILL YOU!" It was rather frightening to see Finn like that- ready to actually kill Flame Princess... until her true form was revealed.

    Season 4 
  • "Five Short Graybles". PB and Peps actually killed a cute little jellyfish for the sake of making the greatest sandwich ever by cooking it. If you think about it, it died in a pretty awful way.
  • The ending of "Web Weirdos", where Finn and Jake are buried under a mountain of baby spiders infinitely gushing out of their mother's backside. During the fade to black.
    Jake: Love like theirs will always find a way. It'll crawl all up over you and drain your body fluids, poisoning you slowly until you pass out.
    Finn: WAAAAAHHHHH!!!
    Jake: Circle of life, Finn. Circle of life...
  • Jake in "Return to the Nightosphere". He turned into some kind of gross demon for real:
    • Nightosphere monsters. One of them looks like it had one side cut off.
    • As they pan across the horizon to show us what the Nightosphere really looks like, the only sound effect that can be heard leaves him shaking in fear. It's a sound effect that sounds like an old woman dying a horrible, slow, painful death.
    • And Marceline's Chaotic Evil form complete with creepy, modified voice.
      Demon!Finn: Marceline... No one... LEAVES THE NIGHTOSPHERE!! RAAAAAAAAGH!!!
    • Marceline's cruel and bizarre punishments. One demon was forced to eternally vomit bananas (and bananas are considered to literally be shit in the Nightosphere,) and one had his entire head turned into abdominal muscles. According to Andy Ristaino, they didn't get better, and their situation is probably far worse right now.
    • The fact that all of the mentally handicapped demons are all locked up in jail, left to either go insane or become even MORE insane. Even more gross is that many cells including the one Finn and Jake were thrown in are filled with bananas, meaning the demons and our heroes were literally wading through demon shit. Or even worse, they could've been horribly traumatized by the horrors of the Night-O-Sphere, which we never get to see.
  • At the end of "In Your Footsteps", the Lich has returned and appears to be plotting something along the lines of vengeance.
    • That scene at night where the bear is standing in front of the mirror, wearing Finn's clothes, imitating him. This creeps Jake out, so he silently walks away, looking just as disturbed and confused as us. It's one of those scenes where it's hard to explain why it's unsettling, but it is.
    • When Finn and Jake are having a nasty argument (lots of shouting), BMO, who just got home from soccer, sits on the floor quietly, absentmindedly rolling his soccer ball back and forth. This brings to mind the way a child reacts to his dysfunctional parent's arguing. The scene is pretty weird and mundane to the average person, but it probably caused countless fans, who grew up in dysfunctional households, to cringe or just feel disturbed.
  • After the climactic hug battle at the end of "Hug Wolf", Finn turns back into a normal boy, and the original hug wolf turns into a surprisingly beautiful woman. After Finn and the woman remark that they both feel like they don't need any more hugs, Jake goes up to the woman ask if he can get a hug, and she flashes a pained look at the ground before spontaneously turning into another Tree of Blight, there's there's a short cut to Jake screaming, and then the episode ends. This isn't as random as it might seem. During the opening scene, the Alpha Hugwolf was hit with a piece of the exploding Tree of Blight. Evidently, this causing the victim to transform into another Tree of Blight, who will, presumably, be dealt with in the same way as the first one. Poor girl.
  • The whole premise behind "Princess Monster Wife," which is essentially about Ice King stealing the princesses's body parts. We see LSP cut open, PB with a chunk of her head missing, and (disturbingly) Turtle Princess with about three fourths of her head gone.
    • The way PB tries to talk with most of her head missing. Incomprehensible gurgling. Sweet dreams...
    • And of course the titular "Princess Monster Wife" in question... 'she' is about as disturbing as you can imagine...
    • The way the Princess sounds- three voices at once. Also a HUUUGE Tear Jerker- as when she cries, we hear three voices crying.
    • The combined Princess is alive... and essentially takes herself apart, which could be seen as killing herself for the good of the other Princesses.
  • PB's frazzled, exhausted, slightly unhinged appearance in "Goliad." We haven't seen her looking so "off" since "The Duke."
    • The fact that PB has made a clone of herself that can live forever. Has she really lost it this time?! We all remember what happened the LAST time she tried making an heir to the throne. Knowing Adventure Time, this will not end well...
      • It DIDN'T end well. Goliad was even WORSE than Lemongrab. LG was an asshole, but PB's newest creation is completely evil and sociopathic.
    • Goliad herself, a sociopathic, telepathic sphinx mutant whose entire premise is based off the alien children from Village of the Damned (1960) (really easily obvious when Finn tries to keep his thoughts away from Goliad). Especially the part with the bee...
      • She crushed the bee in her paws (we saw blood, too!), and brought it back to life with her psychic powers. This made even PB frightened!
      • Her disturbingly logical speech upon her turn to the Dark Side, delivered in that perfect Creepy Child voice:
      "No, Princess. Bee cares not for flower. If getting pollen hurts or kills flower, bee would not care. ::crushes bee:: Bee is stronger than flower. ::reanimates bee:: Goliad is stronger than bee. Goliad is stronger than all..."
      • It's worth mentioning that the hypnotic eye stalk looks and functions identically to Edward's mutated pineal gland in the horror film From Beyond. [1]
      • Incidentally, Goliad was voiced by an actual little girl. And as long as we're here, how about a more realistic version of the battle?
    • The children entering Jake through his eye sockets in an attempt to damage his brain. And when Goliad mind-controls the kids to do the same thing later.
    • Jake freaking out and yelling at the candy kids.
    • The implication that, for all intents and purposes, Finn's son and PB's daughter are doomed to spend the rest of eternity in a meta-world, fighting each other, with no hope of ever coming back.
      • Although, if Stormo inherited some of Finn's Blood Knight nature, he might be enjoying it... which may not be very comforting, really.
    • The implication that (because of Goliad's current state) if PB really DOES die, Lemongrab will inherit the throne to the Candy Kingdom. Oh dear Glob, save us...
      • But it might not be that bad - Lemongrab has settled down with his clone, so maybe they'll rule the Candy Kingdom together?
      • Unfortunately, "Too Old" reveals that Lemongrab has become a sadistic tyrant who oppresses the lemon people and cannibalizes Lemongrab 2. The idea of a disturbed Lemongrab on the Candy throne is frightening enough, but a disturbed, unfettered, sociopathic Lemongrab is even worse!
    • When Finn asks PB why Stormo didn't turn evil, she says it's because he is based on Finn's "heroic DNA". Considering Goliad, who was based on PB, became an evil sociopath bent on ruling the world with mind control, what does that say about her DNA...?
      • It might not be PB's fault. During the scene that depicts what PB put in the formula, one can see Cinnamon Bun getting thrown in the mixture with candy biomass, and climbing out before she puts Algebra in. Cinnamon Bun may have a repressed evil side covered up by his klutzy and thoughtless nature.
      • Also keep in mind that she hangs out with Peppermint Butler almost 24/7. Wouldn't be surprising if tiny shavings (Candy Person Dandrift) from him got in somehow. Or he sabotaged her from the beginning. Who knows?
    • The fact that all this could have been avoided if PB hadn't played God is also pretty terrifying. Making Goliad is one thing but creating another with Finn's DNA... What would happen if Stormo didn't want to fight her?
      • They'd have been exactly as screwed as they already were, so hey whatta ya got to lose at that point? Fire with fire, or mad science as the case may be.
  • "Beyond this Earthly Realm" had plenty to offer in the nightmare department.
    • Finn gets trapped in the Spirit World after touching a magic artifact, leaving him out-of-phase with the real world— he can see and hear Jake, not vice versa. It's a situation eerily similar to Transformers: Prime's Shadowzone, except that Finn lacks the convenience of being able to text Jake for help.
    • The Spirit World is inhabited by a vast collection of bizarre, Lovecraftian creatures that drift about with no rhyme or reason, seemingly just there to creep us out.
    • The only one who can help Finn is Ice King, who's able to see him with his Wizard Eyes. That's not the scary part, though— this reveals that all the crazy things he sees with said eyes actually are real. The whole time, he's been able to perceive the denizens of a world out of phase with our own, akin to the protagonist of From Beyond. He mentions to Finn that they scare him a bit, but that he's relieved that they can't actually interact with him. Once he gets pushed into the Spirit World as well, he's absolutely terrified once the monsters are able to touch him for real. There's also a disturbing rape subtext when he Madness Mantras cries that he's sorry and that he needs Finn's hat as a buffer because they were touching his body.
    • The... head-spitting, Shub-Niggurath-like thingy that stalks the Spirit World version of Ice King's castle. Even he finds it off-putting, which is saying something.
  • Lumpy Space Princess wearing lipstick. *shudder*
    • The shadow Finns in the mirrors. While they're easier to dispatch, they still got in a LOT of claw-swipes at Finn, and if he hadn't been there to break into the chamber filled with them, LSP would be a complete and utter goner.
    • There's a quick scene towards the end of "Gotcha" in which Finn is sitting on a log next to the snail, who, last we've heard was possessed by the Lich. The idea that Finn could be within striking distance of the Lich and not even know it is quite frightening.
    • Between the mirror!Finn undressing and LSP saying that she took it too far/blaming her lumps for turning Finn into a "grody monster", that scene in the mirror room may be very... uncomfortable to some viewers.
  • The previews of "Princess Cookie" are just chilling. A rogue cookie is taking hostages in a convenience store... with a baseball bat as a weapon. We see Princess Bubblegum trying to offer things to the criminal, who screams at her that he wants her crown. Later on, we hear him saying "I'M ABOUT TO FLIP OUT!" Geez...
    • According to Jesse Moynihan, the Tart Toter is "beyond rehabilitation." The way he is now, he'll always be like that.
  • Several faces during "Card Wars". Here's one with Finn. And another. Can't forget this one. This one has Jake. Finally, we have.
  • The entire episode "Son Of Mars" is pretty chock full of it. Magic Man starts the ball rolling by transforming a deer into a telescope, and then neglecting to transform it back afterwards!
    Magic Man: You're welcome!
    • It's lessened when there is the distinct possibility it's that freaky stag.
    • He still has the telescope in Normal Man, several seasons later.
    • All of the torture that Magic Man inflicted upon the Martians- Body Horror, conjoining all of their arms together, bringing their shadows to life to attack them, mutilating them, and replacing all of their drinking water with... Hair...
    • Magic Man's house, which, according to Finn, "is a reflection of his sick mind." It's an old, decaying (literally!) house, broken, filled with mold, and there's a dead rat in the corner. Magic Man seems utterly unaware of how disgusting it is.
    • Magic Man himself. Although he's a very funny character, he's EXTREMELY disturbing. First of all, he tried to have Jake killed just so he could get his powers back- and obviously he felt no remorse. There's also his disgusting lack of empathy for others... and the creepy, sing-song way he avoids Finn's direct questions, such as Finn's inquiries about his home or his girlfriend.
    • On the subject of Magic Man's girlfriend, the King of Mars hints that something happened on Olympus Mons between them which turned Magic jerky. Some promo art for the Sons of Mars title shot reveals his jerkiness may stem from survivor guilt as Margles' appears to have fallen to her death in the dead volcano's crater.
    • THE GUNSHOT. Supposedly, the only way to save Jake was to have Abraham Lincoln travel back in time to Ford's Theatre and be shot again by John Wilkes Booth.
    • Grob Gob Glob Grod's design, which is eerily reminiscent of the Flatwoods Monster.
    • The skull with worms crawling around in it.
    • The 37th Dead World. Note that the tall, skeletal creatures remain eerily still, as if there is no time there.
  • In "Burning Low," Finn almost died of oxygen deprivation.
    • Flame Princess exploding.
    • Flame Princess falling down into the ground.
    • Everything Princess Bubblegum reveals about Flame Princess. She knows how Flame Princess works, and knows that Flame Princess is physically incapable of romance. Basically, Flame Princess is so unstable that if she gets romantic with Finn, she'd cause a reaction that would have her burn into the ground and eventually burn up all of Ooo. The viewers knew how volatile and dangerous Flame Princess can be, but Princess Bubblegum states what exactly could happen.
    • Finn's burned face.
  • The dream sequence from "BMO Noire". There's one part in which BMO has a creepy, male "detective" face, complete with Lemongrabb-ish eyes and a nose. It looked so wrong. Not to mention the images of BMO setting up his detective roleplay implies BMO has a somewhat weak grip on his fantasy life.
    • Especially because we saw that face in shadow, for a split second, making it seem like a subliminal message of some kind. The message? Sleep well, kids!
    • When Finn and Jake come home from adventuring, Finn is carrying a blobby seal-like creature called a "lard" in his arms. When BMO reveals that he found the sock, Finn drops the lard and it doesn't even twitch. While we find out more about it in "Princess Potluck", people can be forgiven for thinking he was carrying a dead body.
  • "King Worm". The entire episode is one horrifying Mind Screw!
    • The title card. It's a mess of giant eyes, Finn/King Worm hybrid vomiting out melting Jake heads, Lady Rainicorn with multiple mouths on her body, PHIL FACE (the face on Mrs. Cow's udder, the face used to open the Nightosphere), all around Body Horror... oh, and The Lich is in the background.
      • The title card music is absolutely terrifying. It can be heard in the episode proper when the Gunter abominations are on the march, but the music's mostly drowned out by the noise.
    • Finn with Lemongrab eyes and a pointy nose.
    • Finn's voice distortion before he describes the sword he want to appear, the whole scene with Jake's Dad, the LSP rain splattering on the ground, Lady Rainicorn's voice, Jake FREAKING MELTING as he tries to assure Finn "Everything's normal...", the King Worm's scary laughter, the Lich coming out of Finn's belly button, the dying Worm King, much EVERYTHING in "King Worm".
    • In Finn's dream, PB is having coffee with the Lich. Finn asks what's up, and PB makes a horrifying Nightmare Face and says "You wouldn't understand, because you're TOOOOO YOOOUUUUUUNG!!!" in a demonic voice.
    • Two giant monsters made of PENGUINS chase after the Ice King.
    • The ghost girl from "The Creeps" makes another appearance.
    • Peppermint Butler appearing and telling Finn how to get out of the dream. Not that the warning in of itself is scary, but because you somehow get the feeling that it was the real PepBut invading Finn's dream, because it seems the sort of thing Peppermint Butler could do.
    • After later episodes from the season, specifically "Reign Of Gunters" and "The Lich", many of these examples become even worse, and watching the episode again highlights some downright disturbing Foreshadowing.
  • The Title Card for "Lady and Peebles." It's so creepy. At a first glance, it's a bunch of photographs of PB and LR scattered on the table. Look closer. Finn and Jake are actually in a lot of the photos. But they're all scribbled out in black pen, as if someone wants to get rid of them...
    • It gets even creepier when you notice that the pictures are laid down on what appears to be intestines, and a couple of worms are slithering over the pictures too!
    • Somehow Ricardio manages to be even CREEPIER in this episode. His face is somehow stranger and it doesn't help that he now has giant muscled arms and legs attached by creepy red sinews and tendons.
    • In one shot, it looked like Ricardio was going to rape PB!
    • The Ice King, minus his heart, lying on the ground, veins and arteries snaking out of him.
    • Lady Ranicorn's speech at the end of the igloo portion. For those who don't speak Korean, she basically talks about a dream where zombies attack her house and kill her family. And she apparently has this dream all the time...
      Lady Rainicorn: I'm little bit too worrying sometimes. I always got haunted by the nightmare that half-dead corpses attacking my house! My uncle, aunt-in-law, cousins were all present, I even hear the crying coming from the upstairs. I just wished that I could protect my family... I become too stressful during that dream, I even grind my own teeth! (Grinds teeth) When I wake up in the morning, all my teeth are cracked up! I usually try to forget about it, thinking that it's just a dream or I'm being paranoid, but I was actually attacked by these half-dead corpses before, twice!
    • What Lady Rainicorn and Princess Bubblegum were attacked by in the episode. Long, grabbing hands, giant eyes that shoot lasers, and a huge tongue. The cave they were in was a Womb Level made from Ice King's biomass.
  • "You Made Me!".
    • Lemongrab watches the Candy People in their sleep. Just standing there, staring, in the pitch darkness, only the glow from his eyes are visible.
    • Lemongrab was creepy enough to begin with- creepy eyes, constant screaming and freak-outs, no sympathy for anyone... And now we're adding "stalker" to the list?!
    • How 'bout all those hideous faces he kept making?! DEFINITELY the expressions of a sane, well-adjusted man!
    • In an animatic released before the episode aired, Lemongrab goes batshit, tries to leap out of a window, and then screams at PB (in a shrieking sort of way we quite haven't heard before), demanding that she give him candy people to rule over.
      • The music that plays in this scene of Lemongrab's freakout is some of the creepiest and most chilling music that has ever appeared in the show. It really helps drive the point that Lemongrab is NOT all together and he's got serious psychological issues.
    • When Princess Bubblegum confronts Lemongrab over his spying on the people of the Candy Kingdom while they sleep, Lemongrab says that he is within his rights. He has the right to break into your room and watch you sleep? Hello, Paranoia Fuel.
    • Princess Bubblegum agreeing that Lemongrab was within his rights to sneak into candy people's rooms and watch them sleep. Candy Kingdom law is messed up.
    • This recent, incredibly creepy drawing of Lemongrab by the lead character designer Andy Ristaino.
    • The title card for the episode, which depicts an allusion to "Frankenstein." Princess Bubblegum is looming over a lab table (on which is lying the earl), holding Lemongrab's nose. She's grinning from ear to ear as lightning strikes behind her through the window, and in the devices in her lab. It's mostly scary because of what we know happens to poor Lemongrab afterwards.
    • A security camera revealed that Lemongrab was in the dark, spying on someone. All that can be seen is his eyes in the darkness... When the camera zooms in, it shows Lemongrab's silhouette, and those same dead, unblinking eyes. Finn's reaction is the same as ours- he screams.
      • It's uncanny how much Lemongrab resembles an Enderman in this scene.
    • "I am alone... and you made me like this! YOU MADE ME! YOU MADE ME! YOU'RE MY GLOB! YOU'RE MY GLOB!", a deranged Lemongrab psychotically yells after jumping out of a window and ripping his clothes off, clearly having a breakdown.
    • Lemongrab continues to go BATSHIT INSANE. The Pup Gang go over to Lemongrab's castle upon Princess Bubblegum's request. He yells at one of them for having headphones on, and starts saying his catchphrase "UNACCEPTABLE!!" and starts descending into utter terror and madness, by going over to a mirror, pointing at HIMSELF in outrage, dramatically turning his head around, and then locks the thugs in a prison and electrocutes them.
      • Lemongrab turning his head around. He doesn't have a neck, and yet he manages to twist his head around almost 360 degrees to make the most hideous, frightening face at the Pup Gang. It isn't cartooney, either. His "neck," or whatever connects his head to his body, contorts and strains noticeably.
      • And he electrocutes them again when Finn and Jake go to rescue them. He amplifies the electricity! Lemongrab at this point is a complete psychopath, and then when Princess Bubblegum tries to confront him, he turns on her.
      • The sheer glee he displays as he tortures them. He SMILES! And as he electrocutes the Pup Gang, he groans, and looks up with this twisted look of almost orgasmic pleasure on his face.
      • As he tortures people in the Conditioning Room, it's difficult to tell if he's insane and unaware that he's hurting people, or if he's a sadist who's all too aware of the pain he's causing. He speaks softly (for once!) and smiles. It ranges from a tiny Kubrick Stare smile to a kiddish little grin to a WIDE JOYFUL SMILE WITH BRIGHT WIDE EYES.
    • Lemongrab's attempt at trying to talk to a citizen of the Candy Kingdom, Crunchy. He started poking him... then started SLAPPING him, then SCREAMED: "PUT YOU IN MY OVEN! IT'S GROOOSS!!!"
      • He doesn't just slap Crunchy. He punches him in the head repeatedly, while making the most hideous and disgusting faces imaginable, while screaming and babbling incoherently. Then, after he yells the aforementioned line, he actually pushes Crunchy onto the ground, and doesn't even seem to care as he cries. It's hard to tell whether he's insane, or actually a sociopath.
    • Princess Bubblegum creates Lemongrab a clone, and they start poking each other. The scene is just... surreal. There's even a Scare Chord in the music. At one point, Lemongrab 1 actually pokes Lemongrab 2 in the eye, and LG 2 doesn't even care at all. Ew! Admittedly, it does end up being pretty heartwarming, but you don't know quite what to think when it starts.
    • The scene where Finn and Jake find the Pup Gang in the Conditioning Room. Lemongrab comes in, sees Finn and Jake in the Conditioning Room... and abruptly shuts the door, trapping them inside.
    • Many of the faces Lemongrab makes throughout the episode. Especially during the sound sword scene. They're just... not natural.This is probably the worst one we get!
    • When Lemongrab backed Princess Bubblegum up in a corner and brandished his sword at her. If Lemongrab clone hadn't shown up, he would have knocked her unconscious with the sound sword and then electrocuted her in the Reconditioning Chamber!
    • Lemongrab's confrontation with Princess Bubblegum. The princess is speaking gently to him and trying to calm him down, but he hunches over and slinks over to her, glowering at her, screaming, and then suddenly, his eyes grow as wide as saucers and become the most manic we've ever seen them. He backs her up into a corner. It's hard to tell who's more terrified of the other.
    • There was something really unsettling about Castle Lemongrab itself. It's empty, VERY minimalistically decorated, and filled with nearly empty rooms that contain only catcher's mitts. There's just something very off about the whole thing.
    • Lemongrab's nasty, big, pointy teeth.
    • Lemongrab when he's calm. There's something... not right about a screaming lunatic suddenly calming down and smiling a cute little smile as he tortures small children.
  • "Who Would Win?" The Farm's all-black, slanted eyes and broken, lolling neck.
    • Jake himself is a source of this in that episode, especially once Finn breaks his portable Kompy's Kastle console and pisses him off.
    Jake: I'm gonna break every bone in your body, then heal you later with that magical goo we got from the Cyclops' eye!
    • They end up beating each other until they're both bruised. At one point, Jake ends up as deformed as Ephialtes from 300.
  • "The Hard Easy" had a pretty terrifying frog monster with its gaping mouth along with the disturbing transformation back to Prince Huge.
    • When the Mudscamp Elder describes how frightening getting eaten by the Mega-Frog would be:
      Elder: I mean, what if you got ate? Think about it: all alone in a stomach full of acid? "Mommy! Mommy, mommy help me!".
    • Megafrog rolling his eyes back into his head as he forces his body into the cave.
  • The trailer for "The Lich" that aired directly after "I Remember You". Seeing The Lich's face zoom in at you directly after Simon Petrikov-era Ice King gives a young Marceline a toy during the Mushroom War is unsettling.
  • The moment after Billy is hit by the gumball guardian, half of his face is gone, revealing that it's indeed the Lich. The fact that the half that's still Billy's face has a single, cloudy eye and skin-flaps? Yeah, creepy.

    Season 5.1 
"Finn The Human" and "Jake The Dog"
  • The mushroom war's mutagenic/nuke turned some poor sod into the Lich. In the Finn's wish universe, that poor sod was Jake the (regular) dog.
    • "He wished for the extinction of all life."
    • The scene where the Destiny Gang not only sets fire to the entire town, but AU!Finn's house. With his FAMILY STILL INSIDE. And they're LAUGHING while doing it. Brr...
    • In the universe Finn created with his wish, it was Finn, via possession by Simon's crown, who caused magic to return.
    • Ice King!Finn in general. He seems more insane that Ice King is normally. "The voices, they tell me to freeze the world. I am the end and the beginning. I am the hand of madness..."
  • Marceline's burned up, still talking skeleton. That she only speaks up to call Finn a "butt" doesn't really soften the blow.
    • AU!Finn kicking Marceline's skull off.
  • So wishing that the Lich never existed would have made Ooo a more peaceful and happy place, right? Actually, in an effort to avert the Lich's creation, it is implied that Prismo altered events so that Ice King!Simon stopped the first bomb that fell during the Mushroom War, which resulted in his death and the crown he wore going berserk and freezing all of Earth for 400 years. This of course averted the mushroom war which Marceline implies would have created the Lich we all know and fear, but in the end, humanity's society had backpedaled a little in technological advancement, they are still as selfish as during the war, Marceline was never bitten by a vampire and thus grew into a very old and crazy lady, AU!Finn took the crown for himself in an effort to save his family but became crazier than the Ice King and caused the bomb that Simon!Ice King had frozen to detonate, resulting in magical mutating nuclear fallout. And to top it off? Marceline died in the explosion and AU!Jake became the new Lich. Not exactly the happy ending Finn was hoping for.
  • Finn in the wish universe looks a like Lemongrab with the eyes and nose. It's kinda... unsettling.
  • When the bomb landed on Simon he weakly called for help, meaning he was only pinned down. You are now thinking about how long he must have lain there before being crushed to death or starved and how desperately Marceline must have tried to pull him out from under it safely, before being forced to leave trapped under what would become his tombstone.
    • Or she didn't find him in time to help.
    • Remember, she was only a little girl at the time.
  • When Prismo explains to Jake how important the wording of his wish is, he mentions that the wishes he grants affect both the past and the future. In other words, one wish could erase memories, cause people to be unborn, and cause entire worlds to either cease to exist or never be created in the first place. Jake becomes so overwhelmed by this, he throws up.

"Five Short Graybles"

  • The last "Five Short Graybles" had Princess Bubblegum and Peppermint Butler crushing an innocent jellyfish to death on screen. This one has the incredibly disturbing imagery of BMO (and "Football") drinking tea, causing visible sparking and burning because of BMO's electronic nature, without knowing that it's killing itself.

"Up a Tree"

  • The "tree cult". They seem at first like the usual Adventure Time goofiness, being a group of cute bickering tree-dwelling animals, but when they catch Finn spying on them the episode takes a sharp turn into the creepy as they chant with blank expressions and surround Finn, the lighting casting eerie shadows over their faces before a howling beaver knocks Finn unconscious.
    "In the tree, part of the tree..."

"All The Little People"

  • Finn romantically pairs up random mini-characters, and we see Marceline licking the red off of Peppermint Butler. Later, when we see how horrible these pairings have turned out, we see that Marceline has licked off half of Peppermint Butler's head.
  • Also, Finn's increasingly creepy behavior over the course of the episode, to the point where he stays in his house for weeks just staring at the tiny people and messing with their love lives. It's implied that he barely moved from his spot at all, not even to bathe. The fact that this is Finn we're talking about here just makes it spookier.
  • The entire soundtrack of the episode (mostly consisting of an off-tune piano) was an intentional use of something called quarter-tone music, where "off-tune" notes (notes with half-sharps, half-flats, etc.) are played along with "in-tune" notes (any note on an everyday piano), producing a spooky and dreamy effect, kinda like this. And they indeed succeeded in producing that effect.

"Jake the Dad."

  • "Baby Eating Fox and the Babies". Paused at just the right moment, a graphic description of the baby being eaten and digested can be read. It's even lampshaded when Jake realizes that the book is a lot darker than he remembers.
    • When Jakes thinks his kids died in their sleep, kids watching may not worry so much, but actual parents watching...


  • The titular Davey takes more than a little persuading before he leaves. It's one thing to put on a costume for a day or two; it's quite another to have it argue against returning to the status quo.
    • When he first starts to become the mask is fairly creepy as well. It's just him laying wide awake at night, murmuring to himself with his eyes wide open...
    "I'm Davey..."

"Mystery Dungeon."

  • Lemongrab still has the ability to contort his non-neck and rotate his head around 360 degrees. Lovely.
    • A manic earl, with a mouth filled with sharp fangs, asking the Ice King "How do you taste?" When the Ice King responds with "Nice, I guess," Lemongrab screams at him.
    • The promo art. It shows Ice King, Tree Trunks, Lemongrab, Shelby, and NEPTR backed up against a wall, staring fearfully up at what appears to be a giant. Ice King is clearly terrified, and is exchanging a desperate hug with Lemongrab, who stares up at the giant in shock, gripping his sword...
    • Lemongrab pulling his mouth open wide to reveal a whole mess of sharp fangs. Eeep.
    • The giant rat that comes through the floor. That in itself is creepy enough. Lemongrab literally punches the rat in the head and the rat either dies or passes out. Lemongrab shoves his face into the mouth of the rat and eats the pre-chewed pie from the rat's mouth.

"All Your Fault".

  • Basically the entirety of this episode. It starts off unnerving, but once Finn and Jake go into the dungeon, it becomes downright terrifying. Lemonjon's giant organs strewn around the castle, the two-headed twitching lemon creature behind the door, the tiny screaming lemon monster whose face peels off, the four-mouthed green lemon creature that licks Jake's hand, and of course, the completely emaciated Lemongrabs that have wasted all their food to give life to these things.
    • It doesn't help that the tiny screaming thing with the peeling head sounds just like a certain other abomination.
    • Put it this way: The dungeon sequence is like a Shout-Out to the Silent Hill games, or possibly the nightmare scenes from Jacob's Ladder, with its random, freaky lemon monstrosities (a two-headed one shakes its head just like one of the monsters from SH or the film), the organs of Lemonjon strewn about, and the darkness illuminated only by light sources haphazardly placed in the area. No wonder Finn and Jake are so freaked out by that place!
    • Princess Bubblegum erasing the candy life formula from the Lemongrabs' exposed brains. They don't seem to mind in the least, but it's still pretty freaky.
      • A Freeze-Frame Bonus of this scene gives us a glimpse inside Lemongrab's brain, and we can literally read his thoughts. And unsurprisingly, some of them are downright awful. One of them reads "Call me crazy, but I think it's time for us to die." Others read unsettling, bold, all-caps things like "RAGE" and "SUFFER." Others imply that Lemongrab is legitimately paranoid and insane, and others imply that he is a pyromaniac who wants to set things on fire.
    • When the Lemongrabs destroy the Candy Seeds to create Seedwad, who immediately goes on to puke. While merely plants, those seeds were already alive, destined to grow into something beautiful and life giving and the Lemongrabs transformed them into a creature that most likely suffers every moment it is alive.
    • Just the fact that the Lemongrabs's stupidity resulted in a child's death, and Lemongrab 2 didn't even seem to care. His complete lack of facial expression was horrible.

"Little Dude"

  • The Magi creature is pretty freaky when he isn't in Woobie mode.

Bad Little Boy

  • At the end, it shows that the Ice King has an entire room filled with Fionna and Cake fanfiction books, with huge ice sculptures of them in the middle. Not to mention that the room is sealed with a lock that looks like Fionna's head, and Ice King dedicating himself to finding Fionna and Cake one day. It's all very... disturbing.

The Great Bird Man

"Simon and Marcy"

  • The mutated zombies. To make matters worse, they are implied have been the human inhabitants of that city.
    • More than that, we see a pink goo that seems to be growing sentient, suggesting that this is a proto-Princess Bubblegum and the goo's behavior (though also a Crowning Heartwarming Moment, provides the much sought-after soup to a sick Marcy) sets the tone for PB and Marceline's whole relationship.
    • From that same episode, the first time we see what Simon is like under the influence of the Crown is extremely creepy. It's like someone flipped a switch and turned this quiet, sweet guy into a cackling maniac.

"A Glitch is a Glitch"

  • The "Glitch" video that the Ice King sends to Finn and Jake. The vid consists of a random emotionless woman eating her own hair. What makes it scary is just how unnerving the vid is. See it for yourself...
    • Probably because her physical reactions (gagging, glancing at the camera) are portrayed realistically, which is seriously out of place for this show.
  • The entire episode is a disturbing eleven solid minutes of pure nightmare fuel, mostly because it's rendered in 3D.
  • "A Glitch is a Glitch" is so terrifying. You watch the inhabitants of Ooo glitch into nothingness as the scenery degenerates into blank polygons.
  • What do you get when you cross a giant spider with a rattlesnake? The stuff of nightmares.
  • No one mentions that the Ice King, usually a Harmless Villain, has come dangerously close to erasing ALMOST EVERYTHING IN THE WHOLE ADVENTURE TIME UNIVERSE???


  • GOLB, the thing that Finn flies by after he "dies".
    • Finn dancing with Roselinen. His arms actually sunk into her sides and disappeared.
    • The Blanket Dragon writhing in pain slowly before it dies. Surprising how a blanket dragon bleeding little pillows can appear so painful and graphic...
    • Heck, the episode itself is disturbing, Finn just experienced an entire life in a day and even died, and doesn't remember a thing about it. It does leave one question, was it All Just a Dream, or did that stuff really happen?

"B-Mo Lost"

  • Bubble the air spirit's shudder-inducing speech to B-Mo at the end of the episode, about how from now on, he'll always be watching him everywhere he goes until the end of time. B-Mo doesn't seem overly affected by it, but it's still pretty creepy to the viewer. The subtle change from happy, heartwarming music to "Psycho" Strings doesn't help.

"James Baxter the Horse"

  • Finn and Jake try to cheer up people at a funeral, but leave when they realize their attempts aren't working. Then the coffin starts shaking around as if the person inside was trying to escape. It's later shown that the person was not actually being buried alive, but the truth is hardly more comforting—later in the episode, they return to the funeral, and the coffin starts shaking again... and out pops a reanimated skeleton that crawls around like something out of The Exorcist, which then becomes an enormous ghost and begins chasing Finn and Jake around, trying to kill them.

"The Suitor"

  • Quite a bit, from Peppermint Butler's demon summoning to the... creatures guarding the Soul Stone. The grand prize, however, has to go to Braco's appearance after he makes a Deal with the Devil to win Princess Bubblegum. Just... UGH.
    • There was a bit more of it too. What with his burning, bruising and bludgeoning, he get's a nice progressive mutilation to bother the audience deeply.

"The Party's Over, Isla de Senorita"

  • The Ice King sneaked into the Candy Kingdom palace, duct taped Princess Bubblegum's mouth and woke her up with a creepy "Hey baby," with the intention of abducting her (as usual) so he can give her breakfast in bed. He does this all the time to the point that it's becoming a Running Gag, but the fact that he considers her his girlfriend even though she (for every good reason) doesn't want anything to do with him drives home how demented the crown made him.

"One Last Job"

  • Gareth splashed Captain Banana Guard with a bottle of banana flavored drink to distract him. It worked and he was shocked that he has tasted "the forbidden flavor". It might not seem much to us but remember that the banana guards themselves are made out of bananas, so to them its like being splashed with a bottle full of blood and guts from another person in the face and getting some on your mouth.
    Banana Guard: It's delicious.
    • Just Jake's position in the entire episode; he's forced to go back to his old life of crime because his daughter is kidnapped. That's every parent's worst nightmare.

"Another Five Short Graybles"

  • The Earls of Lemongrab's section in which Lemongrab 1 starts to eat Lemongrab 2 because the two fought over their "son", just a toy Lemongrab, and dropped and broke it.
    • Just Lemongrab's Start of Darkness in general. Once he tries to eat his brother, he sets himself on the path that leads to his horrific actions in "Too Old" and his death at Lemonhope's hands.
    Lemongrab 2: [holding a yellow hat on his finger] Beautiful...
    [Lemongrab 2 looks back and watches to his horror that his brother is playing with the fragile lemon doll alone, making it frantically dance with his hands]
    [Lemongrab shakes his head before moving the doll towards his cheek]
    Lemongrab: We. Hate. You.
    Lemongrab 2: WAAAAAH!! [slaps Lemongrab, making him drop the doll, whose head shatters on the floor]
    * beat* [Both Lemongrabs stare at each other]
    Lemongrab: ONLY OOOOOOOOOOOOOONE!!!! [bites his brother and starts forcing him down his gullet]
    Lemongrab 2: THE END!!!! MYYYYY EEEEEEND!!!!!!!!
    • Seeing as the Lemongrabs seemed fine in their last appearance, fan speculation has abounded as to what changed between that episode and this one. General consensus, as well as the game being deemed fully canon, is that the experiments that PB put the Lemongrabs through during "Explore the Dungeon Because I Don't Know" managed to screw the two up even more. Seeing as it caused Lemongrab 1 to grow an extra arm and that he's the one with the past negative history with PB, it somewhat makes sense that he's in a much worse place than his brother. That portion of the game can be seen here
    • It worse after "Too Old" reveals that Lemongrab partially ate Lemongrab 2 alive and horribly mauled him to the point of deformity, then abused him and deprived him of food and medical attention.
    • It's also Harsher in Hindsight in that it foreshadows the fate of the REAL lemon children in "Too Old". Lemongrab 2 wanted to put their "son" to bed because he claims he was tired, showing that Lemongrab 2 is a caring father. But Lemongrab wanted the "son" to dance around for his amusement. And then in "Too Old", we see the Floor Show, and Lemongrab's treatment of the children in general compared to Lemongrab 2's.

    Season 5.2 
"Jake Suit"
  • The fact that Jake can control Finn's nervous system seems a bit unnerving.
  • The last part of the episode, where Jake tries to make Finn empathize with him by exposing him to the Fire Kingdom's intense heat without protection, with disastrous results. By the end, both are covered in bandages due to Finn's last stunt, in which he wore Jake once more and jumped into an active volcano.
  • Jake himself becomes terrified of Finn's extreme pain tolerance, as he realizes to his horror he'd probably get himself killed just to prove a point.

"Be More"

  • The original title card for "Be More": [2]Geez, no wonder why they scrapped that...
  • BMO "glitching" and then throwing up is a very real fear- BMO is basically a child so watching Finn and Jake rush him to the Mo Factory was the equivalent of watching two parents taking their very sick kid to the hospital.
    • Moe's emaciated condition, and his sort of Uncanny Valley appearance, especially the way his mouth moves. Softened by the fact that he is an extremely gentle, kind person, though.
    Finn: You're human too?!
    Moe: My skin is!
    • Some of the robots in the factory - they were trying to KILL Finn, Jake, and BMO!

"Sky Witch"

  • Some of Marceline's transformed faces in "Sky Witch" just SCREAM this trope.
    • Maja's face at the end as well as what she is saying while making said face.

"Frost and Fire"

  • The fight between Flame Princess and Ice King goes into a dark place when we see the Ice Kingdom destroyed, its citizens fleeing for their lives, and Finn having to revive an unconscious Gunter and rescue the Ice King from the fire he himself caused. "You blew it", indeed.

"Too Old"

  • Morbidly obese Lemongrab.
    • The creepy lemon child with two heads and no arms/eyes appears again. Although he looks a lot more sad than frightening this time...
    • Because Lemongrab is such a perfectionist neatfreak, it's downright unsettling to see his castle looking so dilapidated and run-down.
    • The fact that Lemongrab's toilet is a giant lemon juicer. It gets disturbing if one thinks about how that works for too long.
    • Lemongrab 2 is revealed to be alive, but his legs are gone, half of his head is gone, he moves around via a levitating hoverdisc, and he looks very thin and emaciated. Made worse by the fact that Lemongrab is starving him and depriving him of necessary medical attention.
    • Basically the entire episode? From Lemongrab abusing his own children to kicking his young son in the stomach to murdering his brother...
      • He didn't just murder his brother, he ate him ALIVE! And when he fights his way out enough to shout to his son to seek freedom and return to save the lemon kingdom, we get to watch him get shoved back in!
      • The dinner table shows that everyone has been served a small amount of food on modest-sized plates- or worse, some of the children have only one piece of bread each. But we clearly see that Lemongrab has a whole enormous feast laid out before himself. He's been hoarding almost all the food to himself, hence why Lemongrab 2 is so skinny and why his children are so hungry and unhappy.
    • Lemongrab's abuse of his children. He put shock collars on them, forced one to repeatedly punch himself in the face while forcing everyone to watch, and he literally kicked his son in the stomach repeatedly, then dragged him off.
    • THE FLOOR SHOW. The fact that Lemongrab was grinning and laughing out of pure delight as he electrocuted his own children and made them "perform" for him. The "performance" consisted of one lemon child repeatedly slapping himself in the face and another lemon child being forced to watch and emit high-pitched shrieks. Even worse because throughout the "floor show," they have looks of complete terror on their faces. Lemongrab tells them to "do it better" before electrocuting the fuck out of the poor kids:
    Lemongrab: Do it better.
    Lemon Child: AAAAAH! AAAAAH!! AAAAAAH!! AAAAAH!!!!
    Princess Bubblegum: I can't watch this...
    • Any scene where Lemongrab tries to eat his brother. Especially during the scene in the dungeon, where we only see his back, with Lemongrab 2 disappearing inside of him.
      • It's especially horrific because Lemongrab 2's hand is shown clawing desperately at Lemongrab's back for a moment, futilely trying to escape. But he becomes too weak due to his illness, and he is swallowed.
    • The scenes where Lemongrab is shown starving his children and even locking one of them IN A BATHROOM.
    • The look on Lemongrab's face as he takes the bread from his son.
    • When Lemongrab is hulking out and he clearly has the strength to smash concrete. Which makes one worry about the safety of the lemon children after PB, Finn, and Lemonhope have left...
    • Some of the lyrics of Lemon Hope's song are just ghoulish, like him mentioning that his pillow is filled with bugs and that he was literally thrown in the garbage and locked in the refrigerator.
    • The Lemon Children are really sweet kids, but some of them were just grotesque-looking, like the ones whose faces appeared to be half-melted.
    • Lemongrab repeatedly electrocuting his children and sending them to presumably kill Princess Bubblegum, Finn, and Lemonhope. And he actually lets out a full Evil Laugh, showing just how irredeemably insane he's become.
"The Vault"
  • "The Vault" finally gives us a backstory for the Green Ghost Lady who first appeared back in "The Creeps": Shoko was a mercenary sent by the Bath Boy Gang to retrieve a powerful amulet from Princess Bubblegum back when the Candy Kingdom was first being built. When she finally managed to get her hand (she was an amputee) on it, she fell from the top of the still-under-construction Candy Castle... right into a river of radioactive slime, emerging later with her arm restored, but also mutated into the freakish worm-monster we see her as as a ghost. Also, when she died as said worm monster, her body was basically consumed by what is now Finn and Jake's tree-house, meaning her skeleton has been hidden in their kitchen floorboards for hundreds of years!
    • Shoko's weird radioactive worm is pretty nightmarish. Have a look.

"Dungeon Train"

  • Just the premise alone. The idea of roaming on a train forever and ever and soon becoming one of the monsters inhabiting it is disturbing.
    • And then there's there are the "bosses" who were implied to be people who endlessly roamed the dungeon. The last horrified look on their face before they died is jarring...
      • It definitely seems like some of the loot is meant to make the adventurers look more like monsters to each other. The whole train seems perfectly designed to eliminate heroes by keeping them addicted with fights and loot and pitting them against each other.

"Red Starved"

  • Pretty much everything about Marceline once she goes insane from hunger. Especially her Nightmare Face...
    Jake: You're sick!
    Marceline: Yeah... [3]
    • The light from the green jewel transformed anyone that crosses its path into sand, killing them in the process.
    • A starving Marceline sucking the pink out of Bubblegum and leaving PB grey and shriveled afterwards. Sure, she does recover, but that was still shocking to watch.

"Play Date"

  • The Cliffhanger ending where Jake is taken to another dimension by Keeoth who had his blood returned to him by Finn breaking Joshua's sword.


  • The zombies from "Simon and Marcy" return from the depths of Ooo to swarm PB's vessel. She sacrifices James to drive them off, but the ending shows James' zombie climbing out of the crater, leading the others out.

"Root Beer Guy"

  • Not only the thought of Finn and Jake going bad, but also the idea of the guards being too stupid and incompetent to solve the case and having to have just a normal guy solve it.

"Blade of Grass"


  • Finn acting like a creeper to Bubblegum in the beginning. The similarities to Ice King's behavior at the start of "The Party's Over, Isla De Señorita" are too much not to be intentional.
    • "I will poke your eyes out, and whenever you try to see stuff, you will think of me." Not to mention that Finn egged Rattleballs on, spreading his eye open and everything. Body Horror, much?
  • The destruction of the Rattleballs. Princess Bubblegum rounds them up at their would-be execution point, speaks to them in a assuring tone, and then... Group 1 go in, *STOMP*, Banana Guards carry the "bodies" away for disposal before the next group enter. Only one Rattleball realizes what is to come and yet he cannot resist. Note that their crushing device is quick and quite efficient for mass extermination. Does This Remind You of Anything?


  • Bella Noche. If you're a wizard, anyway. He's made out of pure Anti-Magic, which, contrary to the trope's description doesn't mean magic doesn't just work on him. Oh no, he takes magic away. Taking Farm World into consideration, the world would be a very different place without magic. So just how much damage would he have done if Betty didn't put a stop to him?
    • When Simon and the gang open the time portal, we get a first hand look at what was likely the first of Ice King's many rampages.

"Lemonhope Story I & II"

  • The entire premise. Lemonhope's personal adventure about eventually releasing the fate of the lemon people by the cruel vast dictatorial hands of Lemongrab. A simple concept to some right?... It's not! Lemonhope becomes a bit of a Jerkass in the very beginning of the first part of the episode and goes out of his way into doing whatever he wants just like the greedy Earl. He escapes from the PB who tried to groom him into a savior of the lemon people but rebukes her. He escapes and goes through various hells. From getting on board a ship that crashes into rubble, nearly starving and dying from dehydration and to top it off on that he has many random bizarre dreams that belie his own guilt. Yet, he later reconsiders in the second part returning to Castle (since turned fort) Lemongrab and goes up against the antagonistic Earl in a dramatic face off ending in what at first appears to be the horrific demise of the crooked Earl but in reality... he gets better.
    • PB and Lemonhope observe a Lemon person trying to escape from Castle Lemongrab: He manages to get over the wall, but he is grabbed by a flying bat creature that takes him to Fat Lemongrab's room, who executes him by eating him alive. The eating takes place offscreen, but we can hear the escapee pleading and screaming.
    Lemongrab 1: I'M GOING TO EAT YOOOOOUU!!!
    • The Castle Lemongrab propaganda video straddles the line between goofy and creepy. It's intentionally So Bad, It's Good, but the subject matter is Lemongrab's children all being put into slavery, while Lemongrab tries to explain that everyone's happy now that 'Hope is gone, even though they clearly aren't, all in grayscale while bizarre depressing music plays in the background. It's also disturbingly reminiscent of certain real-life countries.
    • There's also the ending in Part 2 which shows that once again,the world/Ooo has ended. It's very likely everyone, including Marceline, Finn and Jake and Ice King is dead (For Ice King, this is good since he can be with Betty) apart of Lemonhope and it just gives disturbing implications. Just... what happened that made the world like that again.
  • The brief Jump Scare moment in Billy's Bucket List, when Finn has a flashback which concludes with this lovely reminder of Billy being posessed by The Lich at the end of the fourth season.

    Season 6 
  • Nearly everything involving The Lich in Wake Up/Escape from the Citadel, including his incineration of Old Man Prismo; Billy's face melting away to reveal the Lich's final, fully skeletal form; and the visceral process of the undoing of this form by Guardian's blood.
    • Some of the criminals in Prismo's montage of Citadel prisoners can look worse than The Lich.
    • The above only serves to make the Lich even more terrifying. Not only is he able to escape the Citadel under his own power, but his mere presence destroys it. One gets the feeling the Lich wasn't imprisoned there because he wasn't as bad as the other inmates, but because he's so singleminded in his destruction of life that he simply never thought of committing a cosmic crime before.
    • The Lich makes a horrifying grin as he melts down the Citadel's Crystal Prisons.
    • The Lich's speech to Finn.
    The Lich: You are alone, child. There is only darkness for you, and only death for your people. These ancients are only the beginning. I will command a great and terrible army. We will sail to a billion worlds. We will sail until every light has been extinguished. You are strong, child. But I am beyond strength. I am the end. And I have come for you, Finn.
    • It's eerie in itself how closely Ron Perlman's performance resembles his old monologues as Slade. The similarity in voicing is haunting enough, not to mention the content.
    • Just the fact that after a whole season, the show's most terrifying antagonist is back. And he delivers everything we've come to expect.
    • The Lich casts off Billy's skin and reveals his true form, a skeletal humanoid with spikes down his spine and horns. His voice is clearer, less gravelly, and somehow that makes it even creepier than usual. In this form, he is able to black out the world and isolate Finn with a wave of his hand. He is also able to bring Finn down by speaking one word.
    The Lich: Fall.
    • The Lich's one commanding word that he utters in order to rob Finn and Jake of their power ties in well with the speech that follows The Lich's command. As powerful as The Lich has become as of that point, he truly has risen above strength; his power, his influence, and his reach has become absolute. Finn is no longer facing an enemy that he can fight in a straight battle, an enemy that he can damage or hope that through some amount of endurance he can defeat, even if only just barely. The Lich is beyond strength, all strength; he is death, and not even gods can defeat death.
    • The speech above is powerful and haunting in regards to what it makes The Lich symbolically, and arguably literally, become. Cast in the infinite shadows of the lonely cosmos the Lich represents himself as the embodiment of death itself, an all consuming darkness that will extinguish all light. In the face of such a horrifying enemy, even Finn's strength means nothing, and the way that a single commanding word robs Finn of all his strength shows how absolute his power has become. But God... the worst part is when he reaches out his skeletal hand about to strike at Finn, like he's the Grim Reaper come to collect Finn's soul; it's a very visceral, personal representation of how horrifying coming face to face with Death should be.
    • The Lich at the party becomes this when it's revealed he was aware the entire time, watching, waiting for his moment to strike. This guy has the patience to wait months, being humiliated constantly, just so he can kill the guy keeping him there and escape. That, combined with the fact it's simply impossible to kill him, and the Lich becomes a whole new level of terrifying. This undead engine of destruction who only desires to wipe all life from existence has enough patience to wait months for his chance to get you. You get the feeling his past defeats were little more than an annoyance to him and adds credence to his speech.
      • That one shot where he's in the background, right before he knocks Finn and Jake away from Old Man Prismo is nightmarish. He 's frozen in the same position he has been in the rest of the episode, but his facial expression is different, and it is pure hatred.
      • Hell, the Lich just sitting in the corner peacefully with a little smile on his face is unnerving in its own right.
    • At one point, a Guardian's laser fries off part of Martin's leg. Bone is visible.
      • When the sap is applied to the wound the regeneration process is graphically detailed. You see nerve endings, muscle tissue and fat all reform and then fuse together into a new leg.
      • And then they throw it on the Lich. Here's the process halfway through. The Lich gasped and convulsed in horror as he was turned into Sweet P.
    • The Grass Sword forming a very twisted arm, Tetsuo-style, to grab onto an escaping crystal and then ripping off, taking everything below the elbow with it.
    • Just what does it take to get imprisoned in the Citadel, considering that the Lich has never been taken, and just what did Martin Mertens do to be imprisoned there in the first place? At the very least, Martin is up there with mass decapitations, killing a wishmaster & planetary destruction.
    • It's revealed that even Death is terrified of the Lich. Death! That, alone, is terrifying.
      • The fact should be brought up that the character Death is the personification of a natural death; of a soul moving from one world to the next. The Lich is the physical embodiment of not just death or extinction but anti-life. Let's just let that sink it...
    • To add to all of this, the music for much of both episodes is weird, chaotic, dissonant, and overall adds to the creepiness of the episodes in general. It sounds like a record player trying to play the usual Adventure Time background music, only to do so in a backwards and disjointed manner. Hell, the only music heard while the Lich is turning into a human are screeching violins. It's a bit jarring to hear the regular music at the end of the second part when the setting returns to Ooo.
  • Finn's Sanity Slippage in The Tower.
    • When an innocent, frightened baby deer gets mistakenly swept up onto the tower, Finn doesn't take notice and just idly grabs a rotten apple and grinds on it.
    • The song Finn sings repeatedly in the episode starts to sound like a Madness Mantra after a while.
    Finn: Baby's building a tower into space,
    Space is where he's gonna find his dad.
    Daddy's got an arm, and Baby's going to harm his arm
    By tearing it off his dad.
    • The song has a freakier part later in the episode.
    Finn: Baby's building a tower into space
    To tear off his Dad's arm...
    From like where that round on the arm bone
    Meets that weird flap on the top of the back
    Can pull that until it comes off...
    • Finn struggling to breathe after reaching the atmosphere.
  • In Sad Face, the Ringmaster keeping the Chipmunk captive, and the Chipmunk eating the crowd, even if it was only an act.
  • In Breezy, the LSP x Finn implied sex scene. It comes across as a semi-non-consensual affair, and it's shot in a really creepy atmosphere.
  • The episode Food Chain written, directed and animated by Masaaki Yuasa is full of unsettling things, situations and eerie musical numbers. The Magic Man subjects Finn and Jake to a chain of transformations into birds, bacteria, plants and caterpillars. During this Finn tries to eat Jake, then dies of hunger and turns into the bacteria eating his own dead body. The whole thing ends with Finn ascending to a higher form of existence and becoming a hybrid of all the things he had been turned into.
  • Jake in Furniture & Meat, after becoming power hungry. Breaking into peoples' homes? Creepy. Making them swap places and sleeping positions? Still rather odd, but benign. Forcing them to eat your money and equipment from their toolshed? Now you're crossing the line. Probably worse is that Jake is enjoying it.
    • It was pretty jarring and quite disturbing seeing the normally gentle and kind Wildberry Princess sentencing Finn and Jake to death via pouring molten gold down their throats. Quite a gruesome and painful execution coming from someone who is normally a sweet and timid Shrinking Violet.
  • In Something Big, that moment of Maja and Darren arguing about whether to kill Bubblegum or milk her emotional power. Luckily she gets out okay, but it was a nerve-wracking minute.
    • The moment Darren is awoken from what is doubtlessly a millennia long slumber, the first thing he says is rather creepy. Not helped by the fact that it was almost in a complete, guttural monotone.
      Darren: "I had a dream. I was fighting an army that could birth new soldiers, from their own blood. I was endless. Does that make sense?"
  • In "Joshua and Margaret Investigations" we learn that Jake is half-dog, half-shape shifting alien.
  • In The Pajama Wars Its a bit unsettling how quickly the Candy People devolve into a dictatorship, then a death cult, when they think Princess Bumblegum is dead.
  • In Nemesis, we learn that the entire Candy Kingdom is under constant video surveillance from Princess Bubblegum. No citizen has a single moment of privacy, and most of them are unaware of the myriad cameras spying upon their every move.
    • We also see Peppermint Butler forcing Peace Master to surrender the duel by holding his children hostage and threatening to turn them into monsters. Even worse, he DOES follow through on these threats, and poor Peace Master is left with two of his kids turned into demons. Although the kids don't mind their new forms, it's still quite disturbing seeing him using the safety of children as a bargaining token.
  • Ghost Fly. the 2014 Halloween Special. It starts rather peaceful, but why the titular Ghost Fly appears, shit gets real. The most unsettling moment is when the fly possesses Finn.
  • At the end of Is That You? Prismo comes back to life with a plan he made in case he ever died. Sounds nice, but this involves two things; Finn encounters himself from earlier in the episode, causing past Finn to become the Finn Sword. This prevents past Jake from being woken up from his sleep, turning him into the new "host" for Prismo for the rest of time.
    • Although, on the plus side, Jake seemed quite happy with his fate. After all, getting to sleep in the multiverse's comfiest bed for eternity can't be that bad.
      • The same can't be really said about the Finn that became the Finn sword, Especially after he becomes Fern
  • The Cooler, we see how far Princess Bubblegum would go to protect her kingdom... She had the Ice King cool the Fire Kingdom's magma core so that she could get access to and destroy their WMDs. However, the process of cooling their core was tantamount to starving the Fire Kingdom. PB was shown not just to have Sinister Surveillance, but if push came to shove, she'd be willing to risk committing genocide.
    • We actually get to see an innocent civilian DIE because of the cooling core. Nice going, PB.
  • The Ice King's crown is now more dangerous than before. How? Well, in Evergreen, the original wearer was named Gunter, the same name as the Ice King's penguins, and what Simon calls Marceline when his transformation is complete. Which means that everything the Ice King does that is adorable with the penguins (and even his affinity for the drums) is not Simon's personality showing through, it's the insane fixation of the Crown on its original owner. And also, the Crown is either unaware that time has passed, or is in denial about the original Ice Wizard's death. Simon may just be a Replacement Goldfish and only his willpower keeps his body from fully freezing the world and muttering Gunter to itself forever.
    • And Gunter strongly resembles Finn, and is implied to be his past life. What does the Ice King's Friendly Enemy status mean?
    • There's also something really disturbing about Gunter's insane chanting of "Gunter, No!" that only gets louder and louder as he and his entire world all die seconds later.
    • The entire episode jumps between Tearjerker and Nightmare Fuel very often. The fact that the old ice wizard neglects Gunter, later revealed to be his adopted son, and just how much Gunter wants to be like his dad are tearjerker moments, but the episode adds nightmare fuel since the old ice wizard is directly shown to have been involved in the end of the dinosaurs just because he neglected Gunter. An Aesop for neglectful parents?
    • The Crown's fixation on Gunter is revealed early on in the show. Evergreen says the crown would attach to its original owner, but also that the deepest wish of the wearer of the Crown would be granted. And the Crown clearly became more proficient at keeping its wearer alive and performing ice magic. In "Frost and Fire", The Ice King first says "Save Gunter", meaning the devotion is so strong, it overrides self-preservation. How many people and deepest wishes did it accumulate on its mad search for Gunter before Simon (whose deepest wish was to impress his "princess") found it?
    • To say nothing about the implication that the comet that killed the dinosaurs is a much earlier form of The Lich. In one form or another, he has been around a LOT longer than anyone had suspected.
  • Gold Stars confirms The Lich is still dormant somewhere inside Sweet P. Demonstrated when he full out Mind Rapes King of Ooo and Toronto with visions of primordial beasts in a featureless hellscape.
    Lich!Sweet P: Stop. I have learned much... from you. Thank you... my teachers. And now, for your... education. Before there was time... before there was anything... there was nothing. And before there was nothing... there were monsters. Here's your gold star! (hisses black smoke over King of Ooo and Toronto)
    • Speaking of which, the King of Ooo and Toronto did not seem at all hesitant in "taking care" of Sweet P.
    • At first, Sweet P and Lich speech together in a Voice of the Legion sort of way, which is creepy in a dissonant manner, combining the Lich's sinister voice with Sweet P's gentle and childish one. Then he goes full Lich.
    • This is without debate the darkest, most overlooked episode marking the show's background. We now see a setting similar to Stephen King's Dark Tower series: The beginning of the world was not any nicer than it is now. There was seemingly no beginning. Before time began, existence was nothing other than an incomprehensible realm of chaotic oblivion indwelling screaming Eldritch Abominations. Worse, either the Lich had to have out lived them, killed them all, or be one himself. Like the Crimson King, the Lich means to destroy all of creation, or at least the living factors. Oh, and it gets better. If you pay close attention, you can see Hunson, Orgalorg and Coconteppi among the horde of writhing monsters. Yep. Marceline's dad and Gunter have been around for millennia!
    • After receiving the aforementioned visions, the King of Ooo and Toronto start rubbing dirt in their eyes before running off in terror. Sweet P's innocent response to the entire situation is unsettling as well.
    Sweet P: (Stares at his hands)Just a dream...
  • Dark Purple has a scene where a group of horribly mutated factory workers sing an old commercial jungle in a matter similar to a medieval choral music, almost akin to a Madness Mantra doubly scary because we hear Marceline sing a (much more cheerful version) of the jingle earlier.
  • In Walnuts and Rain, exactly how long was "7718" trapped floating in that ventilation hood? He lived on nothing but rainwater and falling walnuts, causing him to become visibly malnurished. Even worse: his mind has faded to the point where he forgot his own name, he believed his name to be "7718" because he was reading "BILL" from the wrong angle, and he forgot that card games exist despite being a playing card salesman. Given how calm and rational he is when convincing Jake to stay, it's pretty jarring that he's obviously going insane. Imagine being stuck in a black, seemingly endless void for an eternity, barely clinging to life.
  • In "Friends Forever" the Ice King uses the help of another wizard to bring his furniture to life. After the furniture is brought to life the episode gets very dark, with Ice King's furniture purposefully trying to get him to cry and Ice King killing his furniture. Ice King was even willing to kill his own lamp until the other wizard removes life from the lamp. Heck, the fact that the guy whose touch brings life is also able to kill ANYTHING is terrifying in and of itself.
  • Jermaine losing his temper at Finn and Jake because he resents their carefree lifestyle can be a little unnerving to watch, if only because of how physical he gets. As in, not only does he start throwing things at them, but he starts repeatedly punching and biting Jake (again, his BROTHER).
    Jermaine: (to Jake) You got to be Dad's favorite! I GOT STUCK WITH HIS MESS!
    Jake: Come on, Dad didn't have a favorite! He just liked my fart jokes.
    Jermaine: I'M THE FART JOKE! (throws a vase at Jake's head)
  • In "Graybles 1000+", we see Earth as almost entirely devoid of animal life, with two exceptions. We see Marceline's house, looking only a little worse for wear - and there is a light on. While it is never revealed on-screen if Marceline is alive, who else could keep the house so well, despite the age? Then, towards the end, we see a giant white thing chasing after Cuber's ship over the much-crazier Ice Mountains, which then turns and shows itself as the Ice King, with his beard so long it covers his entire body, with the three red gems of the Crown, enlarged, on his forehead. He moves by flapping his beard-wings, as seen in "What Have You Done?". His beard over his own face also forms the face, not of the Ice King, but of Evergreen the Ice Wizard! And judging by his insane cackling, he's finally lost his mind completely. The only people left on this desolate planet are Marceline and this... mad shell of Simon Petrikoff, for whom all hope of regaining his sanity are now lost.
    • Although on a more positive note, it's not made clear WHAT exactly the "Ice Thing" is, so it's possible that it may not be Simon after being fully corrupted by the crown, but rather what's left of the crown after he is cured. It still looks freaky as hell though. "Come Along with Me" fortunately reveals the Ice Thing's actually Gunter, who fused with the Ice Crown. Unfortunately, the Ice Thing apparently went mad after Jake's grandson Gibbon stole one of its jewel eyes to empower himself. It also reveals Marceline's house is now home to Shermy and Beth.
    • Cuber spends a large chunk of the episode fleeing from aliens that are trying to kill him for crashing a wedding and accidentally killing the bride, exposing her to the vacuum of space. "Come Along With Me" reveals those aliens are actually King Gibbon's minions and possible descendants of Jake, which means now Cuber is in Gibbon's sights.
    • Gunter breaking the Ice King's leg with a brick while he was sleeping was a little disturbing too. Cuber also suffered the same injury while fleeing from the aliens/Pups, and is forced to set his leg back in place the exact same way Simon did.
    • In his attempt to get rid of the tracking device PB placed in his tooth, Starchy shoved it in a creature's blowhole, seemingly killing it. Cuber later finds the same creature and discovers it's still alive and starved. That thing was stuck for an entire millenium in the same place it fell, unable to breathe or move. After Cuber helps it, the creature thanks him, showing it's also sentient. And I Must Scream in its purest form.
    • The Prizeball Guardian that comes to Starchy's rescue makes Cuber scream in horror and try to flee from it before the aliens send him flying in the air. Two of the aliens/Pups enter it and shoot Cuber's Graybles bag, destroying the Guardian's head and exposing its candy people (including Crunchy) to the threat of their enemies, the Pup Kingdom.
  • In the episode, "Hoots," Finn's dream is this 100%. We see Finn taking a picture with his dad and Sweet P but they face backwards and Jake's face is upside down. When Jake goes to take a second picture, it's just gibberish, but if you reverse it, he says, "Say goodbye."
    • Princess Bubblegum's nightmare is even worse, with her onw candy people booing her and throwing fruit, then seconds later, melting into some strange yellow substance, the Bubblegum herself falls in it and dies.
  • "You Forgot Your Floaties" had a few moments.
    • Magic Man turning Finn and Jake into an egg and a bowl of soup respectively is pretty unsettling.
    • The reveal that GOLB did...something to Magic Man's wife, Margles, that apparently erased her from existence. Magic Man said that he literally searched every dimension in the multiverse for her, and not even Prismo could bring her back. This means that GOLB is likely the most powerful entity in the series, and he's malevolent.
    • The shot of GOLB sitting alone in the void, staring right at the camera.
    • Betty gaining Magic Man's powers and apparently going insane.
  • In "Orgalorg", Gunter spends much of the episode with his brains exposed. Oh, and he's revealed to be a horrifying Eldritch Abomination who will soon reawaken. And Glob, the only being strong enough to stop him, died a few episodes back.
    • Unless Grob Gob Glob Grod's memories were resurrected within Betty when she donned his (their?) helmet during her and Magic Man's experiments, which means if she can hold it together long enough to focus, there's a chance of defeating the monster.
    • Narm aside; there's something chilling about how Orgalorg in a down to earth casual tone, tells Finn and Jake that they're not going to stop him.

    Season 7 
  • Remember how Finn began to lose himself to Davey? Well, in "Football," BMO performs a kind of "Freaky Friday" Flip with his alter-ego, only for it to decide that it doesn't want to go back, leaving BMO trapped in the mirror world. It gets worse when "Football"'s conscience begins to weigh in and she starts seeing BMO in anything reflective.
  • Marceline getting turned into a vampire. The Vampire King is on top of her holding her down, and she screams and her eyes turns red. The way he's pinning her down as she screams at him to stop could very easily be likened to a rape scene.
  • Many of the Vamps offer some chilling moments. Of particular note are The Moon and the Hierophant. Also the dark essence of the Vampire King.
  • The Moon in particular is the epitome of Nothing Is Scarier. Everything about her is bizarre and unexplained in the most unsettling way possible. She acts like she and the actual moon are one and the same, she has a morbid fascination with pigs and every line she utters in her demonic voice is pure Nightmare Fuel. Finn and Jake are scared shitless by her.
    The Moon: How can you lead me when I am your guide?
    Finn: Are you being literal or allegorical?
    The Moon: He he ha ha ha ha... RAHAHAHAHA!!
    Finn: ME NO LIKE!! RUN, JAKE, RUN!!!
    Jake: But she said that I'm running in her light!!
    • In the climax of her episode, The Moon enters the room and begins making her way towards Marceline very slowly. When Finn and Jake try to fight her, they inexplicably lose control of their bodies and drop to the floor. The Banana Guards' helmets melt in her presence and when she's stopped by a lock, she somehow manages to unlock it by chanting for it to open.
    Princess Bubblegum: (in disbelief) Did you just yell "pigs" until it opened?
  • The Vagina Dentata at Marceline's heart as she begins to suck in the VK's essence. Just a friendly reminder from the writers that Marceline is still half-demon.
  • The title card for 'May I Come In'.
  • The Blank-Eyed Girl from "Blank-Eyed Girl". She's creepy enough to freak Finn and Jake out by just standing there, and the only one who has an inkling of an idea as to what to do is wrong at every turn. Any attempt to ward her off doesn't work, or even causes more of her to appear. And by the episode's end, we still have no idea what her deal is.
    • What's most startling is when the girls start taking off their costumes. At first they remove their contact lenses and wigs, which makes it seem like they were just humanoids playing a prank and Jake prepares to call the police on them. Then the girls' heads spin around and come off, leaving what initially look like stumps underneath. The luminescent Starfish Alien form when they're done undressing is actually less scary than that moment.
    • The fact that the Blank-Eyed Girls are based on the very real lore surrounding Black Eyed Kids.
  • AMO essentially murdering all the other Mos in The Moe you Moe the More You Know.
    • Not to mention his knocking NEPTR, Finn and Jake unconscious.

    • BMO narrowly avoids getting crushed by a series of large machines.
  • From "Crossover": Despite the episode's happy ending, there is now a piece of this new Lich, EVERYWHERE!
    • We also get this lovely bit of dialogue between the Farmworld Lich and his unwitting pawn.
    Farmworld!Finn: That's great! Then we can live everywhere!
    Farmworld!Lich: Everywhere you will die.
    Farmworld!Finn: *nervous laughter* What?
    Farmworld!Lich: You. Your family. Everyone will die. Over and over. Mountains of broken bodies beneath the wheel.
  • Nearly the entirety of "The Hall of Egress." Finn being essentially forced to stay blind is pretty bad, but in fairness he's adaptable (he managed pretty well without his arm, after all) and would likely rise to the challenge. What's worse is the fact that, since opening his eyes is all it takes to send him back to when he became trapped and Jake and Beemo seem intent on getting him to open them (with the best intentions), he exiles himself and is later confirmed to have spent years wandering blindly through the wilderness before escaping. And there's apparently some Year Inside, Hour Outside going on, too, as only a few minutes have actually passed between the start of the episode and the end, so that's an awful lot of suffering packed into a really small timeframe.
    • Unlike the entire other life he lived in an earlier episode, he remembers all of this one.
  • In "Don't Look", the incredibly disturbing implication that all the junk and rats in the hermit's yurt were once people.

    Season 8 
  • The two-parter "Preboot" and "Reboot". Among other things, it's got animal hybrids, a cyborg who implies she's experimented on what's left of the human race, the near Unwilling Roboticization of Finn and Jake, the animal hybrids attacking the heroes as killer cyborgs against their will, Susan Strong's Seeker implants reactivating and overriding her mind with a single-minded purpose to capture Finn and return him to the Founders' Island, the rogue Susan engaging her Phase II mode, the Grass Sword acting against Finn's wishes, and the cliffhanger ending. The Grass Sword merges with the Finn Sword (taking part of Finn's arm again in the process) to make a being who appears to be made of grass. What a way to return from a hiatus!
    • Finn is understandably terrified when he tries to reach out to Susan and she doesn't listen to him, only focused on taking him to their homeland, regardless of his desires.
      Finn: Susan?! Stop, Susan! What are you doing?! Help! JAKE! ANYBODY! Help me! PRINCESS?! SOMEBODY HELP!! AAAAAAH!! HELP!!
  • In "Two Swords," we learn more about the Grass Guy. Apparently, Alternate!Finn (from S6 E19) was living in the Finn sword, and when it was pierced by the Grass Sword (in "I Am a Sword"), a cursed grass creature invaded and trapped alternate Finn in a cocoon, transforming him into the Grass Guy.
  • "Jellybeans Have Power" has Princess Bubblegum attempting to harness her new candy powers. However, in her attempts to defend her kingdom from the Crystal Entity, PB accidentally destroys buildings and injures multiple innocents, something she clearly feels guilty about.
  • The parasitic jellyfish in "Whipple The Happy Dragon". They attach to a host, causing them to see people from their past. Who does Jake see? His dead parents floating in the ocean pleading him for help.
    • Whipple himself is this when pissed off. He can create tornadoes and maelstorms to destroy ships when angry. Unfortunately for Finn and his friends, BMO pisses him off when he reveals the earplugs after being unable to stand Whipple's stories any longer.
      Whipple: Wait... Are you guys wearing earplugs?
      Finn: Uh... I mean, we were, but it was 'cause of the engine noise, not because of you!
      Finn: BMO!
      BMO: He needs to be told! NO ONE WANTS TO HEAR YOUR IDEAS!
      Whipple: I see... I thought you guys were my friends, but, you are all just a bunch of HAAATEEERS!!
  • The Colossus, later known as The Guardian. A giant, incredibly powerful robot that destroys anyone who tries to enter or leave the islands. No one has ever gotten past it. Well, except for Martin and Finn.
  • Alva's video tape, which documents what happened to the inhabitants of the mysterious island. Alva was part of a German research team who came to the island to presumably study it for colonization. Efforts to manipulate the weather with technology were successful... at first. Then the weather spiraled out of control creating freak tornadoes and massive hailstorms. Those who weren't killed by the weather were picked off by the giant animals on the island. Alva was the only survivor.
    • And has apparently been living there alone for decades, from the look of her between now and in the film.
  • The entire society of Founder's Island had a lot of Big Brother Is Watching undertones. Everyone was trained to fit in a specific position, and nobody was allowed to leave the island. As shown in "Hide and Seek," Kara aka Susan Strong was trained since childhood to be a Seeker; someone whose job was to track down Hiders (people who tried to leave the island) and have them sent off to re-education. When Kara tries to help her best friend, Frieda, leave the island, Dr. Gross activates the implant in Kara's head, forcing her to destroy Frieda's escape boat.
  • After a normal day at work, Minerva came home to find her living room ransacked, and her husband and infant son missing. Doubles as a Tear Jerker.
  • The description of what went on with the viral outbreak that led to Minerva needing to undergo Brain Uploading to survive. Over 60% fatality rate on the entire island, but with a 100% fatality rate amongst the Helpers.
    • All the more horrifying in 2020 due to this being prophetic, as doctors and other healthcare professionals are among the hardest hit by the virus.
  • After Finn is reunited with Minerva, she tries to convince him to go through the same Brain Uploading that she did so they can be together again. When that doesn't work, Minerva decides that she has no other choice but to upload the brains of everyone on the surrounding islands. Luckily, Finn manages to talk her down, but it's clear that being in a virtual reality for so long has messed with her head.
  • Just the initial shock of "Elements" right from the get go! Finn, Jake, and BMO return from their island adventure only to find their home and everyone they know and love have been corrupted and warped, with PB now a gigantic tower of gum, Flame Princess a raging fire dragon, and Slime Princess a blob that assimilates her subjects. Not only that, but just being in one of the four quarters has the risk of someone being corrupted by its respective element.
  • More than anyone, the entire "Elements" miniseries has to be terrifying for Sweet P. Because of his powers he's one of the only people not converted by the elementals, but his parents still are, and they want to "fix" him. Imagine the horror of being a toddler and your brainwashed parents trying to convert you into the same transformed creatures they've become.
  • Jake getting assimilated into Slime Princess in the New Slime Kingdom. He just melts into her happily, and Finn nearly does the same until LSP snaps him out of it.
  • The New Fire Kingdom during the "Elements" special. Unlike the other Elemental Cursed areas, where everything is more or less the same but shaded to the color or element of the kingdom (Pink for Candy, Green for Slime, and Blue for Ice), the fire area resembles the remains of a burned wasteland. The whole place has the color scheme of ashes and to top it off, the inhabitants of it become extreme Blood Knights. It's also the first elemental kingdom to corrupt Finn.
    • Finn becomes this once he enters the corrupted Fire Kingdom. His pent-up emotions over Jake being absorbed boil over in the worst way possible, quite literally setting him ablaze with fury. It all starts going downhill when Flambo, who was also corrupted attacks him and his friends. Finn gets pissed off and literally kills him by stomping on him. Finn's horror after calming down is understated, but quite visible.
      Flambo: Talk about a spicy meatba-!
      Finn: You can't run the saw? STAY OUT OF MY WOODSHED! GRAH!!
    • Once they enter Flame Princess' palace, they find the gruesome sight of Fire Kingdom citizens fighting and killing each other relentlessly, as a giant fiery dragon with horns flies above the fighting. When Finn tries to take FP's jewel from its teeth, he realizes to his horror that the dragon IS Phoebe, who's become so consumed by bloodlust and her element that she now wants nothing but to fight.
      Finn: I'mma tear you apart if you did anything to her- Wait... Flame Princess?
      Flame Princess: Return the jewel, worm.
      Finn: AH! It IS you! Listen, I need this to fix Ooo, cause Jake is slime and this place is a toxic aggro machoscape!
      Flame Princess: This place is great!
      [A Flame Person charges at FP and she quickly incinerates him.]
      Flame Princess: FIRE KINGDOM RULES!
      Finn: That was messed up and NOT who you really are! [FP shakes her head]AH![FP throws him off her head.] Gah!
      Flame Princess: Stop talking to me like we're friends! The only friend I have is violence and the only thing we do when we hang is FIGHT!
      Finn Rrrgh!
    • Finn tries to flee with the jewel, but Flame Princess bites his arm and eats it, chuckling at him with an intense cruelty. Finally, seeing how callous Phoebe has become drives Finn over the edge, corrupting him into someone even more bloodthirsty than her.
      Flame Princess: GIVE IT! [roars and bites Finn's robot arm]
      Finn: NO! I have to save Jake! Phoebe! STOP!
      Flame Princess: *gulp* Hnhnhnhnhnhn...
      [Finn's eyes start glowing]
      Finn: Uuuurgh! RAGH!!
      Flame Princess: Gyah! [Finn is corrupted into Fire Finn]
      Fire Finn: I'm gonna ruin your universe!
    • Finn, who was already a Blood Knight, is turned into what LSP calls "a crazy, fiery bad boy", obsessed only with fighting others. He's so consumed by it that he becomes perfectly willing to kill PB.
      Princess Bubblegum: Finn! My little sugar plum. You've returned to accept your sweet fate!
      Fire Finn: I AIN'T SWEET!! I'm a pure warrior with guns, and I'll immolate you for FUNS!!! RAAAH!!!!
  • All throughout the "Elements" series, Betty's had a habit of randomly laughing only for it to come to a head when she betrays Finn and leaves him to be corrupted by the Candy Kingdom, laughing maniacally. Her plan is no better: trying to use the gems to open a portal in time back to before Simon became the Ice King and effectively annihilate Ooo and everyone in it. Prismo and the Cosmic Owl's Oh, Crap! reaction says it all.
  • The ending of "Hero Heart", when Candy Tower Bubblegum starts to slowly convert the citizens of Ooo into more of her brainwashed candy minions while cheerfully singing Bing Crosby's "Let Me Call You Sweetheart".
    Princess Bubblegum: This charade has run its course. In your hearts, you are all SWEET!
    Let me call you sweetheart, I'm in love with you...
    Let me hear you whisper, that you love me too...
    Keep the love light glowing, In your eyes so true...
    Let me call you sweetheart, I'm in love with you...

    • Bonnie's power is so immense it overwhelms Flame Princess', turning her into a Candy Person against her will. In her final moments before she ends up in PB's full control, she gives her jewel to Finn in the only way she's able to, by vomiting a geyser of red jelly beans that look like Blood from the Mouth.
      Phoebe: Aaaaaaah!... No...
      Finn: *gasp* Flame Princess!
      [Phoebe retches]
      Finn: Phoebe?

    • Betty's betrayal of Finn just as he gives her Phoebe's jewel. especially her reaction and Evil Laugh as she leaves on the flying carpet, abandoning Finn to his fate.
      Betty:Gimme them jewels, Finn! We're outta time. Gimme gimme gimme.
      Finn: Here.
      Betty: Hahahahahaha...
      Finn: Let's grab LSP and get the buns outta her- [Betty shoves him off with her finger] Whoa. [hits the ground] Huh?
      Betty: Hahahahaha! Hahahahahahaha! Ahahahahahaha! AAHAHAHAHA! AHAHAHAHA!!
      Finn: I've been betrayed... I'VE BEEN BETTY-TRAYED!! [A corrupted bear comes out of the nearby bushes, staring at him] AH!!
    • The episode ends in a Bolivian Army Ending, with Finn surrounded by PB's army of corrupted Candy and Fire Peoples, and the corrupted wildlife, singing in unison as they approach him. Fortunately LSP rescues him before they can grab him.
  • The finale of the "Elements" Miniseries. Jake is freed from Slime Princess, only to have transform into a monstrous 5 eyed, blue skinned and much taller version of himself. It's then when you realize the form is similar to that of Warren, whom you recall is Jake's biological parent...
  • Patience St. Pim forced the other princesses into performing her ritual against their wills, caused their powers to get out of control, nearly caused an apocalypse throughout Ooo, and remained completely apathetic to the damage she caused, instead complaining that the other princesses didn't want to "play" with her. And the worst part? She gets away with it, receiving no comeuppance for what she did, instead encasing herself in ice when things started going From Bad to Worse, commenting that she'll just try again in the future. Not even the Lich got away with his actions completely unscathed.
    • Adding on to this, it's shown that the ritual totally skewed the personalities of the Princesses in relation to their elements. It's safe to assume the same was done to Patience herself, along with her looks changing as well. So her apathy and ambivalence could be seen more as an affect of her own element being taken to it's logical extremes and not how she would have actually reacted to the catastrophe. And in the end, she freezes herself. So, while everyone else was healed by LSP's work, Patience most likely was not.....
  • A few episodes later we have Ketchup, where BMO and Marceline share stories. Marceline talks about the events in "Elements" and Bubblegum's descent into pure sweetness. The real kicker comes in that once Marceline realizes she's gone, it's implied that Marceline surrendered into sweetdom (or in other words, effective suicide) herself.
  • Being a Lich episode, "Whispers" was bound to have a few moments.
    • Farmwold!Lich tormenting Sweet P through his whispers in an attempt to get him to revert back into The Lich.
    • More of a black comedy example, but Fern's casually suggesting that he stop Sweet P by severing his tendons.
    • The Lich's spirit briefly reawakening inside of Sweet P and speaking in both of their voices again.
    Lich!Sweet P: Quickly, while the boy is gone, we must seek out my Well of Power.
    • Farmworld!Lich referring to himself as the last scholar of GOLB. As if GOLB wasn't scary enough to begin with, he's apparently bad enough to have The Lich as a follower, and our heroes are going to have to deal with him come the finale.
    • Fern, sick of being always second best to Finn, deciding that he should become the only Finn, complete with miming crushing his head.
  • Fern straight up trying to kill Finn in "Three Buckets" once his plan to trap Finn fails.
    • Finn seemingly accepting that Fern was going to kill him.
    • And that's nothing compared to Finn accidentally having his robot arm reduce Fern to shreds of grass. We even see Fern's face contort as Finn's robot arm starts tearing him apart.

    Season 9 
  • Gumbald's monster, Grumbo, kidnapping dozens of Banana Guards in "Wild Hunt". And while we see that a number of them are okay, with the amount of banana peels littered around the monster's hideout, it's very likely that it killed some of them.
  • The Green Knight revealing he's Fern to everyone in "Seventeen" during his arm wrestling match with Finn. He quickly curb-stomps him after that and would've killed him while he was down if Gumbald hadn't stopped him.
    Finn: Hrmm... [The Green Knight starts overpowering his robot arm] GAH?!!
    Green Knight: You can't tell from my face, but I am smiling triumphantly.
    Finn: Nooo! It's... my... BIRTHDAY!!
    Green Knight: I know... [reveals his true face]
    Fern: It's my birthday too.
    Finn: ...Fern?
    [Fern inflates his right arm and quickly overpowers Finn, lifting him upwards and slamming him on the table]
  • The Shapeshifter/Warren Ampersand revealing that he not only planned on killing Jake and absorbing his stretchy essence, but that he's done the same to hundreds of his children in "Jake the Starchild".
    • Worse, when Jake discovered the ruse and managed to regain his stretchy essence, he revealed he has many children to Ampersand who quickly attempts to go back to Ooo to take his grandchildren's essence and kill them as well. When Jake manages to stop him, he ends up killing Ampersand to save his children but ends up stranded in space on a completely barren planet since Ampersand had the only means of getting back to Ooo.
  • The close-up of GOLB as Betty tells King Man that she has a plan to get Simon back, as well as rescue Margles; leaving King Man visibly nervous.
  • The Grand Finale "Come Along With Me/The Ultimate Adventure":
    • A brief flashback to young Marceline during the Mushroom War, standing alone with Hambo against a burning cityscape.
    • Jake's nightmare when he looks for Finn and Fern's vault, although mostly played for laughs, has some disturbing content including seeing his pups turn into vampires and then get cooked by their own mother! What makes Jake scream in horror and cry, however, is what the dream Charlie says to him.
      Dream Charlie: Your farts aren't funny, Dad.
      Jake: NOOOOOOOO!!!
    • We finally see GOLB in all his fearsome glory.
    • GOLB emerging from the portal with no background music, just the sound of what seems to be the portal vibrating.
    • The monster GOLB conjures up, made up of the corrupted bodies of Candy People. Close-ups of those bodies show them in agony.
    • The Gumball Guardian begging for help as it's being corrupted by GOLB.
    Gumball Guardian: Mom, help me. I'm turning nasty.
    • Finn, Simon and Betty trapped inside GOLB, slowly being digested as the walls of his stomach slowly contract around them.
    • Jake goes through a Heroic BSoD after losing a Curb-Stomp Battle against GOLB's monsters and witnessing the treehouse being destroyed.
    • That sound the crown was making as Betty's wishes kept failing and the walls of GOLB's stomach kept closing around her.
    • Betty and GOLB's transformation, while it ends with him in a more benevolent form, is pretty frightening as it's happening.
      King Man: What has she done?
    • Also, the fact that the corrupted Candy People get wiped out near the end of the episode's second half. Yes, without a chance of being turned back. If they did, all of them who were conjured into a monster would have survived.
    • Just the fact that GOLB barely had to do anything to spread chaos and destruction. He's so powerful that he could create Eldritch Abominations just by breathing, and basically nothing anyone did could harm him. If it wasn't for Betty's wish, GOLB would have won and destroyed or corrupted existence itself.