History Fanfic / OperationBUTTERFLY

** In Z.E.R.O., the KND Museum has models of villains that are made out of Earwax (although there, they turn out to be the real deal disguising themselves). Holly finds mention of a villain that made living sculptures out of Earwx in old reports.

* DemographicDissonantCrossover: Let's see. ''Codename Kids Next Door'' is a mostly lighthearted show about kids taking down bad guys, with some dark moments here and there. ''Worm'' is CapePunk series set in a ''very'' bleak CrapsackWorld and centered around a VillainProtagonist who is guilty of murder and numerous other atrocities.

* SchoolBullyingIsHarmless: Averted. Taylor is still horribly traumatized by the horrific bullying she endured at [[SuckySchool Winslow High]], and because of it, she's very reluctant to send Holly to school. Thankfully for Holly, she has [=KND=] operatives at her classmates.

** Holly has a massive pet spider named ''[[Literature/CharlottesWeb Charlotte]]''.
** Danny is implied to know [[WesternAnimation/JohnnyBravo Johnny Bravo]]. Later, it's mentioned a couple of times that Taylor and Holly used to live in Aron City.
** An in-universe news article says that Numbuh 626 was able to work out a deal with several factions attempting to gain control of a chocolate volcano in the Hawaiian Islands. While her name isn't mentioned directly, the fact that she's from Hawaii, goes by the name 626, and is good at working things out between people means it's fairly likely she's based on [[WesternAnimation/LiloAndStitch Lilo.]] This is all but confirmed when Holly and Hoagie go and visit Hawaii and meet 626, and she's a dead ringer for Lilo Pelaki. Word of God, however, is that she is just a shout-out, and not the real Lilo.

* SuperpowerfulGenetics: Holly has the power to control bugs much like her mother. However, unlike Taylor who dominates them, Holly actually speaks to them much like an insect Dr. Dolittle. It seems like her power also makes insects intelligent or aware enough to be able to understand other humans, though Holly still is the only one that can actually have a two-way conversation with them. This is backed up by Worm Canon- Holly is technically a second-generation Cape, and therefore a) her powers, though budded off of her mother's, are different from hers, and b) her gaining them was far less traumatic than a first generation cape's.

''Operation: B.U.T.T.E.R.F.L.Y.'' is a ''Literature/{{Worm}}'' and ''WesternAnimation/CodenameKidsNextDoor'' crossover by [=NullenVoid=] - the same author as ''FanFic/OogwaysLittleOwl'', ''Fanfic/TheExodus'', and ''FanFic/NoPlumbersAllowed''. It is ongoing, and can be read [[https://forums.spacebattles.com/threads/operation-b-u-t-t-e-r-f-l-y-worm-post-gm-codename-kids-next-door.930174/ here]] and [[https://archiveofourown.org/works/30868760/chapters/76216085 here]].

** An in-universe news article says that Numbuh 626 was able to work out a deal with several factions attempting to gain control of a chocolate volcano in the Hawaiian Islands. While her name isn't mentioned directly, the fact that she's from Hawaii, goes by the name 626, and is good at working things out between people means it's fairly likely she's based on [[WesternAnimation/LiloAndStitch Lilo.]]

* LikeFatherUnlikeSon: Holly is a sweetheart, usually calm, and always heroic. Her mother is a retired villain whose family has a history of anger issues (though she does her best to control her temper unless someone ''really'' pisses her off), and [[spoiler:her father is Benedict Uno, a.k.a. [[BigBad Father]], which also makes her a descendent of ''numerous'' villains from fairy tales and mythology, including some like [[Literature/{{Beowulf}} Grendel]] who aren't human]].

* SurprisinglyRealisticOutcome: A few.
** The KND Arctic Base has bad food, because kids, by and large, don't know how to cook much more than instant meals.
** The Arctic Base also has training robots to help teach kids to fight adults, but Numbuh 9 flat out states that learning to fight from a real adult who's sympathetic to the cause would be better.
** The Fake Teen Ninjas freak out once it's pointed out that stealing all the games in the city would mean that video game companies can't survive, since they need money.

* AdaptationNameChange: Sort of, Perhaps unsurprisingly, XXXL is not Professor XXXL's real surname and instead his real name is Xander X. Xavier Largo, similarly Edna Jucation's real surname is Jenkins.

* AntiVillain: Like in canon, Professor XXX-L is a NiceGuy who keeps getting mistaken for a villain by the KND, but this time with the addition that he's a friend of Taylor and Holly's godfather. By the end of RECRUIT, B-52 even states that should downgrade him from an actual villain into a third-party agent, since he's not actively malicious towards kids and most of the conflict with him is because of misunderstandings.

** When Holly asks if they can trick-or-treat at the Delightful Children's house, Taylor, Abby, and Nigel all say no at the same time. Taylor because of the unrevealed history with Father, but as revealed in F.O.U.N.T.A.I.N., The Delightful Children are the ones who made Nigel bald, while Abby failed to save him.

** One of the teenagers that applies to be a cashier at Taylor's store is Kenny. Given that his resume smells of animal fur and that he put down Professor XXXL as his reference, this is Kenny, from the "Kenny and the Chimp" pilot episode that eventually led to the creation of Codename: Kids Next Door. It should be noted that Professor XXXL also came from this pilot. In another nod to the pilot, when Taylor calls for a reference for Kenny, Professor XXXL keeps trying to get Taylor to hire the chimp instead of Kenny, though Taylor declines. In the pilot, Professor XXXL favored the chimp over Kenny, making frequent disparaging remarks towards the boy.

** It is pointed out how ridiculous and self-sabogating a lot of the [=KND=] villains are with their child hater ideology.

* LethalChef: Being staffed exclusively by children under thirteen, it's not surprising that none of the agents at the Arctic Base can cook. Before Holly arrived with her skills learned from helping her one-armed mom in the kitchen the Arctic-Base served up what you imagine children who've never prepared their own dinner would make. B-52 actually sends a message to High Command begging for an actual cook to be sent to the artic base because they don't want to go back to eating 'sad meals', and the senior officers had actually been using official vehicles to get fast food.

* SelectiveObliviousness: For some reason, Monty Uno is allowed to shop at the Supervillain Mart... and just treats it like another store, oblivious to [[CartoonishSupervillainy its usual clientele]].

* SurprisinglyRealisticOutcome:
** Being staffed exclusively by children under thirteen, it's not surprising that none of the agents at the Arctic Base can cook. Before Holly arrived with her skills learned from helping her one-armed mom in the kitchen the Arctic-Base served up what you imagine children who've never prepared their own dinner would make. B-52 actually sends a message to High Command begging for an actual cook to be sent to the artic base because they don't want to go back to eating 'sad meals', and the senior officers had actually been using official vehicles to get fast food.
** While the KND have many positive attributes regarding training, they are ultimately children teaching other children how to fight. Numbah Nine, after getting some pointers from Taylor, suggests up the chain of command that perhaps they could find adults who are sympathetic to their cause to help them train, since while the KND have robots that can ''mimic'' the actions of adults, it's a far cry from an actual adult human in terms of combat ability and intelligence. While 274 is apoplectic at the suggestion, Numbah 100 points out that the KND is against Adult ''Tyranny'', not adults in general, and that while getting adults to help the KND might be distasteful, they can't exactly afford to not take every advantage they can get.
*** Furthering from that, what martial arts that the KND have is not that great in comparison to what a Teen or Adult could manage, because KND operatives have a very limited amount of time with which to actually learn how to fight. An adult or teen could be training for ''years'' longer, and in the case of some older adults, longer than the operatives in question have been alive.
** When Taylor is being attacked by Mr. Boss and his ice cream men, she deliberately avoids using bees since while memetic for her character at this point, attacking with bees is a really bad idea since they're making her honey and bees can only attack once before dying. Unleashing a Bee Swarm could potentially cripple her business. In addition, many of her ground-born insects are taken out of the fight because the cold of the ice cream causes them to go dormant.
** Huff, manager of the [=ToyChest=] Treasures company, berates a worker who claims that a bright side of his video games going missing is that "brats" won't get them. As he points out, kids are the ones who buy the games, so FantasticRacism is a very stupid thing in this case, because if no kids are buying games they lose money.
** Holly tries to look through KND records from Sector V's past operatives... key word being "tries." They are children trying to keep accurate records, so many of them are just plain bad at telling what happened, are atrociously misspelled, or are in comic book form.
** Part of why Taylor moves back to Adultville is that, because of the near-constant villain activity and the damages that it causes, property values in town are ''insanely'' low, since despite how oblivious most of the non-villain adults are, even they would notice the property damage. Apparently there are entire ''neighborhoods'' that are just full of empty houses because they're so in the thick of things that no one will buy them.
** Despite all the child-hating villains in Adultville, the Mayor can't just pass new laws to make kids miserable without a good way to frame it, like limiting arcade hours under the logic that video games are violent and cause criminal behavior, since there's even more adults that like kids, or at least their ''own'' kids, and would oppose it if they didn't think that it ultimately benefits said kids.

* TheParanoiac: Who else but Nigel Uno aka Numbuh One, whose paranoid delusions are so great that even a simple get together barbeque between his teammate's families is enough to get him to suspect even his own father, a known BumblingDad. Unsurprisingly, Holly is a little worried about him.

* GrowingUpSucks: As in the show's canon, K.N.D. agents have this view due to having their memories wiped of their time as operatives when they turn 13. Cree/Numbuh 11 in particular is shown to be having some significant insecurity about how they only have a bit more than a year left before decommisioning.

* LikeFatherLikeSon: Like Tommy and Hoagie, Hogarth also wears flight googles on his face.

** Taylor met Father/[[spoiler:Benedict Uno]] sometime in the past, with the incident in question causing her to move out of Adultville for a few years. The exact details of the incident are rather vague, with Taylor explicitly telling Montgomery Uno ([[spoiler:Father's brother]]) that she doesn't want to talk about it. The only things we do know is that Taylor apparently landed near Father's house when she arrived in the ''KND'' world and that father knows her well enough to avoid going anywhere near her when she's mad (and knows that a giant swarm of bugs indicates she's extremely angry). [[spoiler:It's implied that at least part of the bad blood between them stems from when he turned Sector Z into The Delightful Children From Down The Lane]].

** [[spoiler:The Delightful Children make things personal with Holly during Operation B.A.K.E.D. due to going out of their way to antagonize her both when she helps Sector V try to steal their cake and when she tries to make a replacement cake after that one gets wrecked. Learning that Holly was considering saving some of the cake for them [[DontYouDarePityMe just makes them angrier]]]].

* MysteriousPast: The reason the KND initially investigate Taylor: because KND intelligence couldn't find out ''anything'' about her, not even a birth certificate, and they still aren't sure what to make of her. For the audience, it's unclear just what Taylor has been up to between the events of Golden Morning and now, such as who Holly's father is or how she got from Bet to the KND world - and to top it all off, she's implied to have a past connection with ''Father''.