History NightmareFuel / TheAdventuresOfJimmyNeutronBoyGenius

* ''Win, Lose, or Kaboom'' has the race between Jimmy's team and the team of brainy aliens. When it seems like they have made it to the finish line, they return to Retroville and are greeted by their parents with a celebration of their supposed victory. When they find some things off (like the ice cream tasting like sheet rock), the "parents" urged them to "Eat and Forget" repeatedly in an increasingly unsettling manner like zombies. [[spoiler: It was all a dream implemented by the brainy aliens to distract them; the only way they could wake up is to fall into the void outside where they find out they are in the middle of nowhere. It could be worse, think about what would have happened if the "parents" had captured the kids.]]

* The episode when Evil Jimmy [[spoiler:tricks Jimmy into thinking he's turned good, and creates chaos in the city to distract Jimmy from his real plan, to create a new world that's sapping reality from the Earth, not helping matters is the fact that Clone Earth is every bit as evil as Evil Jimmy is]]. Jimmy proceeds to [[spoiler:reverse the process, presumably killing every one of the billions of evil humans.]]

* "Sheen's Brain" where Sheen's head [[BodyHorror eventually gets so big it takes over his body]]. And then his voice turns demonic when he starts speaking. Worse, his IQ would keep on growing infinitely until ''[[YourHeadAsplode his head explodes]].'' Sheen also becomes a sociopath and KnightOfCerebus -- to the point where he declares himself a God and nearly kills "Ultra Lord" (actually a disguised Jimmy and Carl), his lifelong idol, for trying to revert him to normal.

* "The Evil Beneath" has Dr. Sidney Moist, one of Jimmy's scientist role models and leading researcher in phyto-chemicals compounds thought long dead. He ends up revealing that he's been kidnapping people who come to the Quadrangle to turn them into Algae-based manservants because of his own psychotic paranoia that newcomers were sent to spy on him. He's done this many times and would have successfully done it to Jimmy and his friends if not for Jimmy finding a way to overload the Algae Men and destroy Dr. Moist's lab. Afterward, a dense fog appears out of nowhere with multiple pairs glowing red eyes inside the fog, and Jimmy and flee away in terror.
* "Nightmare in Retroville": Jimmy's monster machine that he created in an attempt to make his friends look like monsters for Halloween actually turned them into monsters, complete with bloodlust, by mutating their molecular structure on a subatomic level and altering their DNA. As such, both Carl and Sheen become bloodthirsty monsters, hell bent on killing or turning others into monsters themselves, with Carl turning into a bloodsucking vampire and Sheen a hungry werewolf stalking Libby.

* "Sleepless in Retroville", where Jimmy, Sheen and Carl have a sleepover with a machine that cranks out scary stories, pillows, and pizzas. The climax is when Carl accidentally creates a flesh-eating pizza that chases them around the house, and a pack of flesh eating pillow go after the parents. At the end after disaster seems to be averted, the pizza monster strikes back - "Haven't you ever heard of sequels?" Then it spirals into a series of nightmares from each of the characters. While most of them are funny, one ends when Carl tries to hide under the parents' bed, but gets stuck and is eaten by the pizzas. ''Yikes''.

* In ''Who's Your Mommy'', Carl gets impregnated by a single alien egg Alien facehugger-style. Jimmy is terrified by the situation and describes how the alien is a glowing mass of energy that could kill Carl via electrocuting him, growing till it splits him in half, or eating his insides once it's born, but everyone else including Carl's parents react with utter joy at Carl's pregnancy. Then the alien, that looks like a giant lightning spewing jellyfish, that laid the egg comes all the way to Earth to look for its baby!

* "One of Us" can get surprisingly scary at times, especially when Jimmy finds himself alone with his rival/potential love interest Cindy Vortex among a city that's been brainwashed and turned into perpetually happy zombies. The ending's rather intimidating as well: as the grandmother boards the mothership, it seems like the episode will only end on a peculiar "WTF" note. Instead, she turns around, lifts her glasses to reveal [[BlackEyesOfEvil completely black eyes]], and says "WE'LL BE BACK." in a [[EvilSoundsDeep terrifyingly deep voice]]. And to make matters worse she returned in a later episode.

* "One of Us" can get surprisingly scary at times, especially when Jimmy finds himself alone with his rival/potential love interest Cindy Vortex among his friends-turned-mindless zombies. The ending's rather intimidating as well: as the grandmother boards the mothership, it seems like the episode will only end on a peculiar "WTF" note. Instead, she turns around, lifts her glasses to reveal [[BlackEyesOfEvil completely black eyes]], and says "WE'LL BE BACK." in a [[EvilSoundsDeep terrifyingly deep voice]]. And to make matters worse she returned in a later episode.

* "One of Us" can get surprisingly scary at times, especially when Jimmy finds himself alone among his friends-turned-mindless zombies. The ending's rather intimidating as well: as the grandmother boards the mothership, it seems like the episode will only end on a peculiar "WTF" note. Instead, she turns around, lifts her glasses to reveal [[BlackEyesOfEvil completely black eyes]], and says "WE'LL BE BACK." in a [[EvilSoundsDeep terrifyingly deep voice]]. And to make matters worse she returned in a later episode.

* The episode when Evil Jimmy [[spoiler:tricks Jimmy into thinking he's good, and creates a new world that's sapping reality from earth]]. Jimmy proceeds to [[spoiler:reverse the process, killing every one of the billions of evil humans.]]
** Many of the evil duplicates of Jimmy's friends, family, and acquaintances are shown to be highly disturbing. Evil Jimmy's parents are shown to be the most deranged as Evil Judy is shown gleefully dirtying her house while Evil Hugh laughs sadistically after recounting how he killed and mounted ducks on his wall after they begged for mercy.

* The animation in this show. Growing up in the early 2000s back when most cartoons used 2d animation, the style seemed creepy and off-putting to some children. Especially the Jimmy-Timmy Power Hours, where characters who had always lived in a 2d world suddenly became computer-generated big-headed kids.

* Cindy being strangled by a boa in "Stranded" is PlayedForLaughs but her pale blue face, bulging eyes and overall painful expression make it look like she really ''is'' about to die.

* Jimmy's entire situation in "The Eggpire Strikes Back". Picture yourself in his shoes: you saved your town from an evil alien race some months ago, and they come back for, at first, unknown purposes. Instead of taking over right away, they claim to come in peace and bring everyone gifts, emotionally manipulating the town with their own interests and desires. [[CassandraTruth Despite your efforts to prove their true intentions, the town that you protected starts doubting you as the alien race in question takes it over.]] By the time you finally figure out what it is they're planning (reviving their dead chicken god to feast on the town), you've become a social pariah to everyone, including your best friends, and even your parents are embarrassed of your supposed prejudice. Then the truth comes from the alien leader's mouth: they all want to get revenge on ''you,'' the boy that put a stop to their plans the first time. They plan to [[KickTheDog leave you begging and pleading for everyone to believe you about their imminent doom, only to watch helplessly as the people you know and love are devoured one by one, all while your enemies simply laugh at your failure]], all caused because of your heroic actions. That's what Jimmy has to go through; if it wasn't for Cindy [[MyGodWhatHaveIDone realizing she helped the Yolkians with their evil intentions]], this episode would have ended [[KillEmAll quite a bit differently]]...

* The Nanobots proceeding to delete everyone from existence due to them being "flawed", thinking they're doing their jobs correctly.

* ''Win, Lose, or Kaboom'' has the race between Jimmy's team and the team of brainy aliens. When it seems like they have made it to the finish line, they return to Retroville and are greeted by their parents with a celebration of their supposed victory. When they find some things off (like the ice cream tasting like sheet rock), the "parents" urged them to "Eat and Forget" repeatedly in an increasingly unsettling manner like zombies. [[spoiler: It was all a dream implemented by the brainy aliens to distract them; the only way they could wake up is to fall into the void outside where they find out they are in the middle of nowhere. It could be worse to think about what would happen if the "parents" have captured the kids.]]

* "One of Us" can get surprisingly scary at times, especially when Jimmy finds himself alone among his friends-turned-mindless zombies. The ending's rather intimidating as well: as the grandmother boards the mothership, it seems like the episode will only end on a peculiar "WTF" note. Instead, she turns around, lifts her glasses to reveal [[BlackEyesOfEvil completely black eyes]], and says "WE'LL BE BACK." in a [[EvilSoundsDeep terrifyingly deep voice]]. And to matters worse she returned in a later episode.

* Jimmy's entire situation in "The Eggpire Strikes Back". Picture yourself in his shoes: you saved your town from an evil alien race some months ago, and they come back for, at first, unknown purposes. Instead of taking over right away, they claim to come in peace and bring everyone gifts, emotionally manipulating the town with their own interests and desires. [[CassandraTruth Despite your efforts to prove their true intentions, the town that you protected starts doubting you as the alien race in question takes it over.]] By the time you finally figure out what it is they're planning (reviving their dead chicken god to feast on the town), you've become a social pariah to everyone, including your best friends, and even your parents are embarrassed of your supposed prejudice. Then the truth comes from the alien leader's mouth: they all want to get revenge on ''you,'' the boy that put a stop to their plans the first time. They plan to [[KickTheDog leave you begging and pleading for everyone to believe you about their imminent doom, only to watch helplessly as the people you know and love are devoured one by one while they simply laugh at your failure]], all because of your heroic actions. That's what Jimmy has to go through; if it wasn't for Cindy [[MyGodWhatHaveIDone realizing she helped the Yolkians with their evil intentions]], this episode would have ended [[KillEmAll quite a bit differently]]...

* Jimmy's entire situation in "The Eggpire Strikes Back". Picture yourself in his shoes: you saved your town from an evil alien race some months ago, and they come back for, at first, unknown purposes. Instead of taking over right away, they claim to come in peace and bring everyone gifts, emotionally manipulating the town with their own interests and desires. [[CassandraTruth Despite your efforts to prove their true intentions, the town that you protected starts doubting you as the alien race in question takes it over.]] By the time you finally figure out what it is they're planning (reviving their dead chicken god to feast on the town), you've become a social pariah to everyone, including your best friends, and even your parents are embarrassed of your supposed prejudice. Then the truth comes from the alien leader's mouth: they all want to get revenge on ''you,'' the boy that put a stop to their plans the first time. They plan to [[KickTheDog leave you begging and pleading for everyone to believe you about their imminent doom, only to watch helplessly as they're devoured one by one, while they simply laugh at your failure]], all because of your heroic actions. That's what Jimmy has to go through; if it wasn't for Cindy [[MyGodWhatHaveIDone realizing she helped the Yolkians with their evil intentions]], this episode would have ended [[KillEmAll quite a bit differently]]...

* Jimmy's entire situation in "The Empire Strikes Back". Picture yourself in his shoes: you saved your town from an evil alien race some months ago, and they come back for, at first, unknown purposes. Instead of taking over right away, they claim to come in peace and bring everyone gifts, emotionally manipulating the town with their own interests and desires. [[CassandraTruth Despite your efforts to prove their true intentions, the town that you protected starts doubting you as the alien race in question takes it over.]] By the time you finally figure out what it is they're planning (reviving their dead chicken god to feast on the town), you've become a social pariah to everyone, including your best friends, and even your parents are embarrassed of your supposed prejudice. Then the truth comes from the alien leader's mouth: they all want to get revenge on ''you,'' the boy that put a stop to their plans the first time. They plan to [[KickTheDog leave you begging and pleading for everyone to believe you about their imminent doom, only to watch helplessly as they're devoured one by one, while they simply laugh at your failure]], all because of your heroic actions. That's what Jimmy has to go through; if it wasn't for Cindy [[MyGodWhatHaveIDone realizing she helped the Yolkians with their evil intentions]], this episode would have ended [[KillEmAll quite a bit differently]]...

** Captain Betty's backstory is pretty creepy too, despite the {{Bathos}} surrounding it. He was harvesting sea monkeys (here depicted as actual monkeys) for a mail order company when suddenly his ship was attacked by the monster. Not only did the monster eat his hand, as shown earlier, but it also devoured ''every last one of the sea monkeys he caught''. The ominous way he tells the story, right down to describing the sea monkeys' screams, implies that the incident traumatized him (possibly explaining why he's so loony now) and it haunts him even to this day. [[MoodWhiplash And THAT'S]] [[ComicallyMissingThePoint why they call him Betty!]]

%% * Don't forget forget to mention Johnny Quasar, the first ever Jimmy Neutron short. It's much more deranged and creepy.
* The episode where Jimmy, Sheen and Carl have a sleepover with a machine that cranks out scary stories, pillows, and pizzas. The climax is when Carl accidentally creates a flesh-eating pizza that chases them around the house, and a pack of flesh eating pillow go after the parents. At the end after disaster seems to be averted, the pizza monster strikes back - "Haven't you ever heard of sequels?" Then it spirals into a series of nightmares from each of the characters. While most of them are funny, one ends when Carl tries to hide under the parents' bed, but gets stuck and is eaten by the pizzas. ''Yikes''.

* Many of the evil duplicates of Jimmy's friends, family, and acquaintances are shown to be highly disturbing. Evil Jimmy's parents are shown to be the most deranged as Evil Judy is shown gleefully dirtying her house while Evil Hugh laughs sadistically after recounting how he killed and mounted ducks on his wall after they begged for mercy.

* The episode when Evil Jimmy [[spoiler:tricks Jimmy into thinking he's good, and creates a new world that's sapping reality from earth]]. Jimmy proceeds to [[spoiler:reverse the process, killing every one of the billions of evil humans.

* "Sheen's Brain" where Sheen's head [[BodyHorror eventually gets so big it takes over his body]]. And then his voice turns demonic when he starts speaking. Worse, his IQ would keep on growing infinitely until ''[[YourHeadAsplode his head explodes]].'' Sheen also becomes a sociopath and KnightOfCerberus -- to the point where he declares himself a God and nearly kills "Ultra Lord" (actually a disguised Jimmy and Carl), his lifelong idol, for trying to revert him to normal.

* The episode when Evil Jimmy [[spoiler:tricks Jimmy into thinking he's good, and creates a new world that's sapping reality from earth]]. Jimmy proceeds to [[spoiler:reverse the process, killing every one of the billions of evil humans. He killed a species. That's genocide. And what's worse: If he didn't ''his entire planet would die.'']] [[WhatDoYouMeanItsForKids Pretty dark for a kids show.]]
** Many of the evil duplicates of Jimmy's friends, family, and acquaintances are also shown to be highly disturbing. Evil Jimmy's parents are shown to be the most deranged as Evil Judy is shown gleefully dirtying her house while Evil Hugh laughs sadistically after recounting how he killed and mounted ducks on his wall after they begged for mercy.

** And that episode reveals that she can shoot lasers from her eyes, which she uses to disable Goddard. And then there's the following comment she makes after Baby Eddie insults her.
-->'''Grandma Taters''': I could just eat you up! '''''[[BlackEyesOfEvil ANd mAyBE]] [[EvilSoundsDeep I WilL]]!'''''
-->''Eddie understandably [[BringMyBrownPants poops himself]]''
* In "Stranded!":
** Cindy being strangled by a boa is PlayedForLaughs but her pale blue face, bulging eyes and overall painful expression make it look like she really ''is'' about to die.
** The giant spider [[FromBadToWorse (especially if you have arachnophobia)]].
* The Nanobots proceeding to delete everyone from existence due to them being "flawed". [[FridgeHorror If Jimmy hadn't intervened before they hit the "empty recycle bin" option...]]
* "Sheen's Brain" where Sheen's head [[BodyHorror eventually gets so big it takes over his body]]. And then his voice turns demonic when he starts speaking. Worse, his IQ would keep on growing infinitely until ''[[YourHeadAsplode his head explodes]].''
** Brain!Sheen in general is a big KnightOfCerebus, courtesy of WithGreatPowerComesGreatInsanity as he develops PsychicPowers and {{Sociopath}}y the more his head grows -- to the point where he declares himself a God and nearly kills "Ultra Lord" (actually a disguised Jimmy and Carl), his lifelong idol, for trying to revert him to normal.

* When one of the Needleheads is forced to eat a banana cream pie, his head explodes. His headless, burnt stalk is left wandering around comedically for the rest of the movie, but still very unsettling. It's presumed a Needlehead's head can grow back.
* The Twonkies. Indestructible, vicious, and downright ravenous little Gremlin-like creatures that are drawn to destroy sources of good music, that start off looking like adorable little puffy creatures before coughing, gaining black eyes, and sprouting claws. Worse off, if you put too many of them in one place, they'll merge to become a massive indestructible Twonkie.
* ''Flippy'' turns out to be pretty dark considering it's Slappy from the R.L. Stine Goosebump series UpToEleven. To explain, Hugh purchases another puppet named Flippy (the first got torn apart by Twonkies twice then turned into firewood) to practice ventriloquism but his comedy routine is lacking, so Jimmy puts a computer chip in Flippy's head to enhance Hugh's brain. Instead, Flippy uses the chip to draw consciousness from Hugh to give himself sentience and become a real person who happens to be malevolent and pretty sociopathic, while Hugh loses his mind and becomes a lifeless empty shell. [[EvilHasABadSenseOfHumor Not to mention joking about how he took Hugh's brain, planned on marrying Jimmy's mother, and skipping town to go to Las Vegas.]] When Jimmy caught on, Flippy threatened to destroy Hugh's brain since he controlled Hugh's body. When he gained full sentience, Flippy planned to kill Hugh by chucking his body off a cliff so Hugh couldn't get his brain back. Worse off even though Jimmy manages to destroy the chip it's implied in the end Flippy is still alive and still has some control over Hugh's mind.
** The episode makes some startling implications about what runs through Hugh's mind considering how evil Flippy was despite having the same mind and interests as Hugh.
* In ''Trading Faces'', Jimmy and Cindy's minds switch into each other's bodies after an experiment goes awry. Comedy aside, the more their minds are in each other's bodies the more they start to think like the mind they switched with. Imagine inhabiting someone else's body and slowly losing your mind until you start to think like that someone.
** The process in which it took to put them back into their own bodies could also count to some degree, as the two were strapped down to tables, electrocuted into unconsciousness, and then something resembling their minds/brains was extracted and poured into a jar during the procedure.
* In ''Who's Your Mommy'', Carl gets impregnated by a single alien egg Alien facehugger-style. Jimmy is terrified by the situation and describes how the alien is a glowing mass of energy that could kill Carl via electrocuting him, growing till it splits him in half, or eating his insides once it's born, but everyone else including Carl's parents react with utter joy at Carl's pregnancy. Then the alien, that looks like a giant lightning spewing jellyfish, that laid the egg comes all the way to Earth to look for its baby! [[spoiler: [[NonMaliciousMonster It all turns out alright and the Alien's birth is a harmless endeavor]], but the possibility was there.]]
* Baby Eddie in ''Clash of the Cousins''. Like Jimmy, he's a super-genius who's perhaps even smarter than Jimmy due to being able to outsmart Jimmy while still an infant but is completely malevolent and tried to kill his entire family to gain his Aunt Amanda's money. Think Stewie Griffin but UpToEleven in terms of evil.

** Don't forget forget to mention Johnny Quasar, the first ever Jimmy Neutron short. It's much more deranged and creepy.
* Jimmy being reduced to a gelatinous slab after running around too fast. His body will eventually re-stabilize into solid matter.
** And for a side of FridgeHorror, had Jimmy ''not'' turned into purple gelatin before impact he would have splattered all over the pavement. ''In front of his friends,'' no less!
* A candy that ''electrocutes your mouth'' if you eat it.
** Even more disturbingly, this doesn't deter Sheen from continuing to eat the candy. In the final scene, he mentions smelling smoke, his face being numb and seeing blue from all the shocks he's getting from eating the candy.
** How about the reason why Jimmy invented the electric candy? Earlier in the episode, Jimmy invents a candy that's so delicious, it becomes addictive. It gets so bad that everyone becomes like drug addicts and even try to ''kill Jimmy when he dumps all the candy and tells every one that there's no more.'' Even his parents become addicted! It only takes the electric candy to make them stop.
* The episode where the gang goes to Retroland to try to disprove a ghost myth, with different people showing up dressed as the ghost to try to scare them. At the end, the real ghost appears to Jimmy's parents.

* "The Evil Beneath" is actually full of this. The plot follows Jimmy and his friends investigating to find the reason behind the string of boats and planes that disappeared in an area of the sea known as the Bahama Quadrangle. When they get there, they find Dr. Sidney Moist, one of Jimmy's scientist role models and leading researcher in phyto-chemicals compounds thought long dead. Though he comes off as a silly and goofy weirdo who likes tap dancing, he ends up revealing that he's been kidnapping people who come to the Quadrangle to turn them into Algae-based manservants because of his own psychotic paranoia that newcomers were sent to spy on him. He's done this many times and would have successfully done it to Jimmy and his friends if not for Jimmy finding a way to overload the Algae Men and destroy Dr. Moist's lab. After they destroy the lab and think they solved the mystery, a dense fog appears out of nowhere with multiple pairs glowing red eyes inside the fog (implied to be evil porpoises based on the screeching from the fog) and Jimmy and the gang decide to leave the mystery unsolved before fleeing away in terror.
* "Nightmare in Retroville", appropriately enough for a Halloween special, has plenty of this. Jimmy's monster machine that he created in an attempt to make his friends look like monsters for Halloween actually turned them into monsters, complete with bloodlust, by mutating their molecular structure on a subatomic level and altering their DNA. As such, both Carl and Sheen become bloodthirsty monsters, hell bent on killing or turning others into monsters themselves:
** Carl cuts his finger, starts sucking on his blood and actually ''enjoying'' this (because he's just starting to become a real Dracula), much to Jimmy and Sheen's disgust and confusion.
** Sheen the werewolf stalks Libby for some time before approaching her, which we can see from his creepy first person perspective.
** While it's not shown on screen and we never see any bite marks, both boys actually end up biting Cindy and Libby. Before that happens, we can see Carl's mouth slowly approaching Cindy's neck, and Libby screams for her life (definitely ''not'' in a G-rated manner) once Sheen jumps onto her. You could imagine a RealLife sexual assault playing out similar to these two encounters.
* The DNA Productions logo screen at the end of every episode doesn't help much. A theme music similar to an OminousMusicBoxTune plays, and then a 3-eyed monkey jumps out, looks at the screen, and says (in a weird, squeaky voice) "HI! I'M PAUL!" It can be slightly disturbing for some viewers.
* At one moment in "''Monster Hunt''," although the exchange between Carl and Sheen is played for laughs immediately after, upon interpreting Captain Betty's gibberish about using Jimmy's technology [[spoiler:to catch a Lake Monster]], something both cryptic and very unsettling is revealed:

** Captain Betty's backstory is pretty creepy too, despite the {{Bathos}} surrounding it. He was harvesting sea monkeys (here depicted as actual monkeys) for a mail order company when suddenly his ship was attacked by the monster. Not only did the monster eat his hand, as shown earlier, but it also devoured ''every last one of the sea monkeys he caught''. The ominous way he tells the story, right down to describing the sea monkeys' screams, implies that the incident traumatized him (possibly explaining why he's so loony now) and it haunts him even to this day. [[MoodWhiplash And THAT'S]] [[ComicallyMissingThePoint why they call him Betty!]]
* During ''Sorry, Wrong Era'' at some point off screen Hugh traumatized a poor woman by making her "Experience the miracle of birth ''again and again and again.''" Which means he used the time remote on her to make her re-experience giving birth to her baby multiple times. She breaks down in hysterical tears as she explains to Judy what happened.

** The process in which it took to put them back into their own bodies could also count to some degree, as the two were strapped down to tables, electrocuted into unconsciousness, and then something resembling their minds/brains was extracted and drained into a jar during the procedure.

** The process in which it took to put them back into their own bodies could also count to some degree, as the two were strapped down to tables, electrocuted into unconsciousness, and then something resembling their minds/brains being extracted and drained into a jar during the procedure.