Nightmarefuel / Codename: Kids Next Door
How scary can an old man be?

What's too scary for kids nowadays? Just because it's the Kids Next Door doesn't mean the show's not willing to make even the most stoic and badass of both Kids and adults shiver in fear. Suddenly getting decommisioned doesn't sound so bad.

  • A.R.C.H.I.V.E. Is a fairly dramatic (if slightly comical) parody of "Second Renaissance", which in-it of itself is rather scary. And just as it seems everything is going to be fine, the tone suddenly shifts to this violent bombardment of hostile imagery, psudeo-gory objects, screaming and a scare chord. Thank god Uno's teacher stopped it before it got out of hand.
    • The Stinger at the end of the episode revealing that atleast SOME of Uno's conspiracy theories are true, though wether or not this episode is even canon is debatable.
  • The Delightful Children are terrifying when you know who they really are, and what happened to them. They used to be Sector Z, until they were captured by Father himself, and put them through such rigorous torture (or as he puts it, Delightfulization) to the point that's it's quite literally IMPOSSIBLE to turn them back (any attempts are just temporary). To think that such honorable members of the KND have been turned into such monsters is not only scary, but you have to think of what kind of treatment Father put five ten year olds through, not to mention that the delightfulization was so intense that they work as one being.
    • Not to mention the Adult Fear and Fridge Horror that sets in when you can't help but think about Sector Z's parents. Their real parents. Try to put yourself in their shoes: they all had to live their worst fears when their kids never came home, and they most likely NEVER found out what happened to them. Doubles as a Tear Jerker.
    • Operation F.O.U.N.T.A.I.N. reveals that the Delightful Children were responsible for Nigel Uno's permanent baldness. It is implied that is was Numbuh 5's great failure, as she blames herself for not saving Numbuh 1. How they managed to do it is unknown.
  • Heinrich, Numbuh Five's nemesis, trying to dunk a live rabbit in molten chocolate. Terrifying. Even worse when he soon after tries to dunk Abigail herself into the molten chocolate. And Heinrich used to WORK WITH Abigail before! And then Heinrich fell into the chocolate and became an eldritch abomination! And finally, the fact that Heinrich is really a pretty little girl!
  • Even though he's a minor villain, Chester has perpetrated some of the most extreme acts of Nightmare Fuel in the series against not only KND operatives but regular innocent children as well. Worse off he doesn't do it out of pure insanity like most villains on the show, but out of unbridled greed and apathy towards sacrificing children to make a buck.
    • In Operation C.A.M.P., Chester held innocent children against their will to use child labor to produce lanyards and wallets at low prices as part of a moneymaking scheme. He then revealed he brainwashed them to become his slaves and had them attack Sector V before trying to kill Bradley the baby skunk by throwing him into a lake.
    • In Operation: F.A.S.T.-F.O.O.D., Chester enacted what was possibly his most despicable plan ever (and possibly the most gruesome operation of any villain in the entire series): opening a fast food restaurant called Burger Frenzy, where kids visiting the restaurant would be captured and used as the meat on burgers which are then sold to sharks to be eaten. He nearly succeed to having Numbuh 3 sold to sharks and would have continued on with other innocent kids if he hadn't been stopped.
    • In Operation: U.T.O.P.I.A.., Chester created the "Happy Headband", which trapped the victim in a virtual reality in which they experienced a personal paradise. He intended to sell it to parents as a product designed to keep children under control by basically brainwashing children into believing they're in a dream world. When Numbuh One was captured and placed in a dream world, Chester revealed himself by manifesting his head and face on all the people in the dream world to attack Numbuh 1.
    • In Operation: S.A.F.A.R.I., Chester disguised himself as a doctor who gives vaccination shots for "Moosebumps". However, he later reveals shots he gives to kids actually cause Moosebumps, which literally turns the victim into a moose. Chester intended to saw off the antlers of his victims and use them to make "Chester's Marvelous Moosicles".
  • The Crazy Old Cat Lady in her first appearance, what with her merging her cats together and all.
  • Bradley's accident in Operation: H.O.S.P.I.T.A.L. He's hit by a car and mortally injured, while on an undercover mission to spy on Numbuh 5's older sister, Cree. What's worse is that we get to see how he got in first person. Good news, he was sent to a hospital. Bad news, a team of surgeons, including Numbuh 5, failed to save his life. Even worse, the hospital was the base of Cree's current operations. The way she managed to pick off Sector V one-by-one is terrifying, especially when this happens in a hospital. Not to mention Cree tried to "scramblify" Bradley's brain with a power drill hidden inside the head of a Rainbow Monkey toy before she found out he was a skunk, meaning she was fully willing to possibly kill a gravely injured child in his hospital bed.
    • R.O.B.O.-B.R.A.D.L.E.Y is terrifying himself. Half of his body is replaced with cybernetics and he managed to defeat Cree in a one-sided battle. In Operation S.I.X., he has combs for claws that can crave wood.
  • Father, at least before his Villain Decay.
    "It appears you just aren't ready for the adult world, Mr. Uno. I believe it was time you were... FIRED!"
    • Heck, even after, there's an episode where he turns most of the KND into into animals. It's...not pretty. Just ask Abby, who, while being turned into a Gazelle, is screaming in agony. The others promptly follow suit.
Grandfather. Sure, Father was scary, Grandfather takes it to another level. Sure, he's got some humor, but overall, he's just scary. To elaborate, he's capable of turning anyone he touches into a citizombie...which naturally have the same ability as well. He's even capable of zombifying the world in a sense, turning it into a colorless world with tapioca factories for KND treehouses. His reign was implied to have been like one big old time Child Labor sweatshop taken Up to Eleven.
  • In the same film, Numbuh 362 getting infected. Yes, even Numbuh 362 is helpless against the senior citizombies, who proceed to infect her and turn her into one of them. Not to mention that while most of the Senior Citizombie transformations are frigthening, hers was probably the most so because it was seen from her perspective. The shot in question involved a zombified Numbuh 60 with smirking sadistically and putting his hand over her face to transform her. Imagine everything going to black for a moment and then becoming evil when it cleared up. It's pretty easy to feel her fear. This only shows just how dangerous the senior citizombies are, as even the harmless Toiletnator can effortlessly induce infection with a simple touch.
  • The backstory is even more nightmarish when you consider Grandfather actually ruled the world. What the hell did he do to have been able to topple every government in the world?!
    • Presumably same thing he did in the present, turned most of the adults into Senior Citizombies and enslaved the kids to be slave labor.
  • The Pirates of the Caribbean parody episode. Somehow, turning into licorice skeletons seems scarier than turning into regular ol' skeletons. And that's not mentioning what happens to them when the sun comes up...
  • Cree's Berserker Rage in Operation V.I.R.U.S.
  • The delightfulization process. Can you imagine being permanently brainwashed into being evil?! There's also the fact that you're probably alive and aware throughout the entire ordeal and maybe even afterwards...
  • Numbuh Three when she's pissed. She's just plain scary, especially her appearance. And her anger gives a whole new meaning to Beware the Nice Ones.
  • The show gets a large portion of its Nightmare Fuel from Fridge Horror and Adult Fear. Adults who enslave their children? Corrupt Corporate Executives that can and WILL kidnap your kids for cheap extraterrestrial labor? Dean Bitterman, the Scary Librarian, and even the Evil Teacher taken Up to Eleven? LICE THAT CAN GROW TO BE THE SIZE OF SMALL CARS? It's a GOOD thing the Kids Next Door is in charge, or the world would be a serious Crapsack World, and NOT JUST FOR THE KIDS...
  • The fourth grade class president shoving the reprogrammed boyfriend helmet onto Lizzie's skull as it fuses with her head!!
  • Operation P.O.P., where kids are being shoved into giant bottles of root beer. It's played very seriously.
    • Numbuhs One and Four had it worse. They both got shoved into a bottle meant for one person.
    • What's worse is that in real-life, these kids would undoubtedly die a very painful death from suffocation or simply because their organs were crushed from being in such a confined space. Thank god for cartoon physics.
  • In Operation N.A.U.G.H.T.Y, um....well... let's just say there's a VERY good reason why only Santa is allowed to use the REINDEER System.
  • The Chicken Pox, as in, living chicken heads grow out of your face
  • The Delightful Children From Down The Lane, even without knowing their backstory, they're still creepy regardless especially the episode when one of them pretended to join the KND, after he revealed his true nature and rejoined the Delightful Children, he simply... slid into place *shudder* adding to the fact they talk in unison like a Hive Mind, as if the writers were thinking "You know the Children of the Damned? Let's see how far we can emulate that while still keeping a G rating"
  • The episode where Count Spankula turns Numbuh One into a spanking vampire. The entire treehouse is on lockdown til sunrise, it takes place in the middle of the night, and the colors change to a deep red, while the kids are stalked and picked off one by one, without even seeing who is after them.
  • The recent teaser shows Numbah One seriously contemplating whether he should do something drastic to Earth because it's too overrun with adults. Whatever it is, Chad is there and freaking out, and he even reminds him of all the innocent people who live there, seemingly trying to avoid serious collateral damage. It's all for naught, as One goes through and prepares to bring havoc to Earth, egged on by his new peers in the GKND. What the heck happened to Nigel during his time in space?
    • The fact he is willing to potentially kill the rest of Sector V, people who he loves so much.
    • Even scarier is the Rainbow Monkey website that leads into the G:KND ARG, where you can input names of characters, groups and places to get responses. What happens when you input 'Father'? DANGER DANGER DANGER Yeah, even the GALACTIC KIDS NEXT DOOR is scared of the guy.
    • The implications are profoundly terrifying, too. Basically, the GKND are the Nazis, except the target of their genocide is everyone over 13, not the Jews. Is more than 66% of your species' population over 13? Bam. Your entire race is massacred, whether your life expectancy is 25 years or 1,200 years, no ifs, ands, or buts. The entire Universe can be inferred to be one giant Crapsack World, and it's all the GKND's fault. Just like Numbah 3 said, "Holy fBEEPk"
  • Operation S.A.T.U.R.N. was a creepy episode all in it's own. The whole backstory for Ramon-4 is just creepy in it's own the robotic remains of a space experiment that after being shot into space, it's plush and fur rots away and joins with other floating space junk and develops god like powers. creepy...
  • Operation W.H.I.T.E.H.O.U.S.E. takes place in a bad future where Numbah One is the President of the United States, and is about to sign "The Bill of No Rights for Kids". The only thing discussed is how it would lead to the dissolution of the KND, but it gets much, MUCH worse. The bill would essentially strip children of their basic human rights, and reclassify them as inhuman at the least, and "life unworthy of life" at the most. The bill also seems to be an instance of Did Not Think This Through, as the signing of such a bill could cause widespread secession among the states and most likely start a Second Civil War, which, considering how advanced military technology is compared to the 1860s, would be much more deadly and destructive and most likely escalate into World War III as other nations would come to the aid of the seceded states and remove the current, genocidal (even omnicidal) American government. Just think of the ensuing Crapsack World where kids would most likely be herded into concentration camps and most likely killed en masse in a Child Holocaust, essentally turning the United States into Nazi Germany. Fortunately, the whole episode was All Just a Dream.
  • In Operation: C.A.K.E.D.-F.I.V.E., a Kids Next Door operative from the 1800s is thawed out after having been frozen in an ice cream explosion for over a hundred years. This is terrifying when you realize that everyone he ever knew is long dead (including his parents and any siblings he may have had), and he will have to adjust to life in a world that has changed so much that he is now entirely unfamiliar with it. His decommissioning might have helped in that it would have removed some memories of his previous life, but he still would remember non-KND related things.
  • Operation G.H.O.S.T. becomes this with the inclusion of the ghosts of dead hamsters that once powered Sector V's treehouse. After Kuki's beloved hamster Chubbo dies, she and the gang bury him in the yard below before Kuki wishes she could take care of Chubbo after his death. The ghosts of hamsters past then rise from their afterlife to haunt and drag Kuki back to the hamster afterlife to care for the hamster ghosts for all eternity. After she refuses, the ghost afterlife instantly becomes chaotic and the hamster ghosts become enraged snarling ghouls that attempt to chase down and kill Kuki and her friends. After they escape, the ghosts rise from Chubbo's grave to become a large snarling hamster ghoul to finish off Sector V, but are quickly warded off and appeased using soda fired by the hamsters living the Treehouse.
  • Three words. GREAT. WHITE. ASPARAGUS. Sounds ridiculous? Well, in addition to looking like a worm-like creature that simply should not 'exist', its basically Bruce the Shark, but with much less restraint. What puts it above most creatures that usually menace kids in cartoons? [Near Villain Victory It does indeed devour all the 5 KND operatives, sans Abby at the last minute. The ocean is certainly a better place when Stickybeard kills off the thing and frees the eaten operatives.