[[caption-width-right:300:[[NightmareFace "Oh, hey there, cutie. Aren't you beautiful?"]]]]
For [[NightmareFace a]] [[DerangedAnimation show]] [[WhatDoYouMeanItWasntMadeOnDrugs like]] [[WesternAnimation/TheMarvelousMisadventuresOfFlapjack this]], there's a lot of scary stuff.
* In general, Thalassophobia. You fear sea monsters? Fear being far away from home? Fear how big and empty the ocean feels? Hell, maybe you just fear water itself. Then this cartoon [[NightmareFetishist may]] or may not be for you!
* The episode "Fancy Pants". In order to get into Peppermint Larry's VIP section of the Candy Barrel, Captain K'nuckles has to get a pair of fancy pants. But since K'nuckles is...well, K'nuckles (i.e. dirt poor), he can't buy a pair. However, there is a free pair, but you have to be incredibly obese to wear them. While trying to figure out a way to gain enough weight, Flapjack suggests to K'nuckles that he should eat a ton instantly fattening "candy-coated hot dogs". Seeing K'nuckles eat the food is bad enough, but what comes at the end of episode is even more horrible and [[BigLippedAlligatorMoment completely out of left field]]. K'nuckles finally gets into the V.I.P. section, but all of a sudden '''he explodes, filling the place with a billion hotdogs and a sea of BLOOD.'''
* [[http://www.youtube.com/watch?v=2MEA7yF2jxE The cat]] which provides our [[SarcasmMode lovely]] page image. '''''"Eeeeeeuuuuhhhhh..."'''''
* In "Foot Burn" an old hag shouts at Knuckles causing his face to rip off. The results are very detailed.
** The hag herself is also pretty disturbing.
* Almost all of " K'nuckles Is a Dirty Rat" is nightmare fuel. What with all the extremely detailed, extremely grotesque, plague infested citizens, Dr. Barber, and the random song about giving someone the plague just because they won't be friends with you.
* "Pun Times with Punsy [=McHale=]" has a scene where he scares Flapjack by telling him puns as his head enlarges and turns to all the colors of the rainbow. ''"You think you're RED-y for my rhymes!?"''
* The acid trip like sequence K'nuckles has in "K'nuckles' Hilarious Problem".
--> Candy Wife: "I'm delicioussssssss." *shudders*
** K'nuckles has pulled plenty of [[NightmareFace nightmare faces]] in the episode.
* The character Dr. Barber. Here's an explanation: being in a show that is ''WesternAnimation/CourageTheCowardlyDog'' combined with ''SpongeBob'' and ''WesternAnimation/TheRenAndStimpyShow,'' he's one of the scariest characters there. Plus, he's involved in most of the scary scenes of the show-- like the freak-out scene from ''K'nuckles and His Hilarious Problem,'' ''Fish Heads,'' and ''K'nuckles is a Dirty Rat.''
** The episode "Fish Heads" has the K'nuckles and Flapjack selling hundreds of fishheads [[NauseaFuel for various purposes such as toothpaste]]. Then, when Doctor Barber gets a hold of the two's fish heads, [[spoiler: he creates a giant hair...fish...thing which was supposed to give everyone perfect haircuts, but instead gave them horrible haircuts. That's not all.]] It's a lot scarier in action.
** Gone Wishin' has the mermaid which [[spoiler: decays over time from K'nuckles wishing, and then her horrifying transformation sequence.]]
** "Unhappy Endings" has a scene where Flapjack and K'nuckles decide to hear a story from Dr. Barber. Dr. Barber tells the story of how they actually want surgery, so Dr. Barber gives them his tea and starts doing...'''[[BodyHorror SURGERY]]'''.
* Flapjack's nightmare from "Tee Hee Tummy Tums". What is scary about it is that it comes straight out of nowhere.
* In ''Panfake'' Peppermint Larry uses DEAD RATS as puppets! While Flapjack and K'nuckles are helping Peppermint Larry by cleaning out the Candy Barrel, Flapajck stumbles upon an old box, Larry remembers that the box has his old puppets in them so he pulls them out to show him. When he pulls them out, Flapjack just flops to the floor screaming in terror. From a distance they look like rubber cartoon rat puppets, then Larry has to use them to point out they're puppets and we clearly see they're dead rats tied to strings! "shudders" [[JerkassHasAPoint no WONDER the Dock hag shut him down!]]
** A subtle but terrifying detail is that at first Larry voices each puppet one at a time. Then he somehow voices both puppets ''simultaneously''. Either he is the greatest ventriloquist of all time or the puppets can really speak.
* That mechanical genie...
** The creepy imagery of "How The West Was Fun". Vast, endless ocean, sea monsters, and finally, the disturbing segment at the end where Flapjack and K'nuckles plummet off the ends of the earth. The animation switches to black and red, and becomes distinctly surreal as the two scream in terror as they're swept away into the dark, unknown country. [[spoiler: Thankfully, its only a hallucination brought on by drinking sea water. They're really just freaking out on a raft, and are saved by Bubbie]]
* The sight of Flapjack cheerily ''tying knots in Bubbie's intestines'' in preparation for the Knot Tying Festival. The fact that everyone treats it so lightly just adds to the MindScrew factor.
* In the episode "Skooled", from the very start, you get to see a bunch of leftover limbs inside Eight-Armed Willy's mouth. While not bloody, these limbs are still fresh and only got their outer bones visible.
** It gets worse, K'nuckles gets into [[PunnyName Ms. Leading]]'s school during night to steal some candy. When he sees her, he thinks she just uses silent treatment, but then realizes that she's a puppet (Ironically saying "I feel mis...lead!") as well as her students. Then, tentacles appear from the ground and grab hold of Ms. Leading and her students, which start to talk to him in a creepy innocent voice.
** [[FromBadToWorse It STILL gets worse]], when Flapjack arrives to school, the teacher says that today she will teach them about '''FEAR''' with a [[NightmareFace slightly nightmarish face]] and creepy deep voice. K'nuckles, full of fear, writes to Flapjack but the teacher intervenes and reads it, in which case '''IT''' goes in a total rage full of twitchy movement and environmental colour change. [[spoiler: '''Then a tentacle breaks her whole face and body.''' Good thing it was just a puppet.]]
** [[spoiler: [[NightmareRetardant Oh, don't worry!]] It was not Eight-Armed Willy, it was Ms. Leading herself dressed as Eight-Armed Willy! K'nuckles and Flapjack get candy after learning which is right and which is left.]]
* In one episode, [[https://www.youtube.com/watch?v=jHyU0craHKg there is a scene]] where Flapjack tells a presumably young boy to grow up. After the boy tells Flapjack he is 38 years old, we get a close-up of his wrinkled face. His expression immediately cuts from a somewhat-happy face to an expression of desolation as a disturbing instrumental plays in the background. The same scene is also shown at the end of the same episode.
* The episode where they go to Syrup Island, which they discover to be dark, covered in a strange green mist, and completely deserted, aside from a withered old man named Lord Hotcake who they find in a decrepit old cabin. He claims that all his workers mysteriously disappeared when the mist rolled in (though the scariness subsides when he states that the mist is actually the noxious perfume of an unpleasant frenchman). However, the episode quickly becomes scary again when K'nuckles and Flapjack helps the old man recover his strength by making him some syrup, and he suddenly turns on them and reveals that the reason all his workers left was because he wouldn't pay them, and he's just been waiting for people to show up looking for syrup so he can ''enslave'' them.
* K'nuckles telling a story about a sailor he knew once who cursed at the sea for drenching him with a surprise wave, and as punishment, the ocean filled his mouth with jellyfish which ended up ''fusing his mouth together''.
* The grown men pretending to still be children at the Stormalong Orphanage.