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Plot Tumor

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"For a bunch of guys on a mission to save the world, you sure do love your detours."

A single plot element that was once a minor part of The 'Verse swells in importance as the series progresses, growing more in focus and elaboration to the point that it becomes the focus of major arcs and plot development. As a result, the Plot Tumor's tentacles get wrapped around other elements of the work, either via retcons that connect the Plot Tumor to things it wasn't originally conceived for or just by crowding out other elements in the story.

Typically, this occurs when the creative reins pass on from one writer to the next, as writers forget the original quirks of the element or their creative juices enable them to actualize the untapped story potential of taking a small but notable aspect and expanding on it. However, it's most visible in Derivative Works, where a single element that was important in the source material's success becomes the major focus of the adaptation, especially if late-to-the-party fans or non-fans of the original don't realize the Plot Tumor was once a small part of the original storyline when the work was first being published and it can seem almost unnatural for it not to be part of the status quo of a derivative work.

Keep in mind, however, that Tropes Are Not Bad and fandoms expound on minor details just as much as canonical writers; sometimes with the latter ending up into the former.

Compare: Adaptation Decay, Flanderization, Romantic Plot Tumor, Never Live It Down, and Motive Decay. A Malignant Plot Tumor is the single-plot counterpart, where a minor plot at the beginning crowds out the other plots at the climax. Contrast Adaptation-Induced Plot Hole.


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    Anime and Manga 
  • Yukito Kishiro derailed Battle Angel Alita: Last Order for a two-volume gothic vampire story which acted as last-minute background for "Fata Morgana" (a nanotech super-program). It would appear the Fata Morgana became such a Plot Tumor due to Kishiro's understandable reluctance to pull a Deus ex Machina on his readers, but it's still not the most elegant arc of the series.
  • Dragon Ball:
    • Ki attacks and powering up. At the beginning of the original Dragon Ball, there were no ki attacks, and the first of them, the Kamehameha Wave, didn't appear until the middle of the first arc. Even then, it was sort of the trump card, came at a high cost, and wasn't played terribly often. As the series progressed, though, the Kamehameha became a more standard attack, and ki attacks became more and more prominent. Then, DBZ came along, and it became the main premise behind practically everything the fighters did. They could fly, teleport, power up, etc., all based on Ki manipulation. Ki attacks eventually led to Beam Spam, and the ability to power up that was introduced early in DBZ became the method by which nearly every Big Bad but the last one was defeated, by digging just a little deeper and becoming just a bit more powerful.
    • It's interesting to note that Dragon Ball started as an homage to Journey to the West, then it got a little martial-arts focused and eventually drifted so far, you almost forgot the original purpose of the story was to find the Dragon Balls. Past two-thirds of the series, the balls were so easy to recollect again by the good guys that by the first arc of DBZ they're mostly assembled off-camera, and the bad guys were no longer focused on getting wishes from them and settled for the destruction of the world and the rest of the cosmos.
    • Starting with Battle of Gods, the serialization of Dragon Ball Super has a heavy focus on the Gods. While Gods have already appeared in the franchise before, they were usually weaker than the heroes, but with the introduction of Gods of Destruction and Angels, the relevance of Gods has escalated, as most plots revolve around Gods and their conflicts or the heroes trying to obtain godly powers. Even worse, the Gods of Destruction made the Power Creep even worse than before, like Frieza did in his first arc.
  • In Food Wars!, the introduction of Erina's estranged father propels a two-year long arc that gradually focuses more and more on the Nakiri family's drama, at the expense of actually progressing Soma's journey in the cooking world. It gets to the point where Erina's character development is more plot-relevant than Soma, that by the epilogue the author is more concerned with adding more details to the Nakiri family lore than actually have Soma achieve any of his initial goals.
  • Newtypes in Mobile Suit Gundam. About two thirds of the way through it somewhat abruptly moves from a sci-fi war story to a sci-fi war story about psychics. Many major characters turn out to be Newtypes, they turn out to figure into the backstory, some fairly important characters have motivations involving them... Later background material revealed that the idea of Newtypes was a big thing Zeon Deikun (the founder of what became the Principality) talked up to convince people to move into space, by suggesting that if people did so then more "enlightened" Newtypes would arrive to lead humanity to a golden age of peace through their heightened understanding of other people. It also reveals that Deikun was completely full of it and didn't believe a word of what he proposed about Newtypes, simply saying whatever he thought would make moving to space sound good; that people with psychic powers actually started showing up a couple decades later was a massive coincidence.
  • Naruto:
    • The Uchiha clan, and Sasuke in particular, only became more prominent in the story as time passed, to the point where the Uchiha clan is responsible for the entire plot of the manga. Sasuke started out as merely The Rival to Naruto (though he clearly had greater story importance than other such rivals due to also being Naruto's teammate) who wanted to avenge his clan, but as the Uchiha presence expanded, so did his. He arguably had more face time in the manga than the actual protagonist, and in the series' climactic arc, it's mainly Uchihas who accomplish anything of importance since two of them are the main villains, and a third single-handedly negates the mass revival technique that nobody else could stop. It's a sore spot between fans whether this is a good thing, a bad thing, or something in between.
    • The First Hokage possessed a rare ability to control wood, something done by combining water and earth elemental chakra. In the beginning, this was just one of ten possible chakra combinations, with no reason to believe it was any more special than lava chakra (combined fire and earth chakra) or ice chakra (combined water and wind chakra). As the series has progressed, however, the importance of the First Hokage's cells, which innately possessed this ability, has grown to the point where the amount of characters that possess them rivals the amount that possess the sharingan, another ability that is supposed to be exclusive to the aforementioned Uchiha clan.
    • The Sage of Six Paths. Originally just the man who was the first user of chakra and supposed progenitor of the Uchiha and Senju clans, and later the one who brought the tailed beasts into being by defeating a worse creature and splitting it up, it eventually turns out that Naruto and Sasuke, and Hashirama and Madara before them, are direct reincarnations of his sons, his mother is actually the Greater-Scope Villain, and her "third son" Black Zetsu has been manipulating the world since the Sage's time to try and bring her back.
  • Yu-Gi-Oh! is possibly one of the finest examples in fiction. The manga focused on many types of games at first, and Duel Monsters (Magic & Wizards) was only meant to appear in one chapter. Fans kept asking if there were real versions of those cards available and if the game would be revisited, which it was—without it the series would have been canceled very early on. The author realized that focusing on a single game allowed him to have more story focus, and so it became the focus of long story arcs in the manga, became the central focus of the anime, and snowballed until the entire franchise centers around it to the point where non-card games are very rare. Spin-offs have gotten to the point where Duel Monsters created the universe, and even in series without magic, the Solid Vision systems and VR might as well be magic in how monsters are "alive" and interact with opponents.

    Comic Books 
  • Animal Man eventually started drowning in "the Red" (which eventually led to Animal Man ditching superheroics completely in favor of animal activism).
  • The Flash and the Speed Force. The Speed Force started as a way of Arc Welding all of the unrelated super-speedsters while providing them with a universal Hand Wave for the ways that they make physicists cry. It eventually gained enough properties, applications, and relevance that it now dominates the Flash mythos.
  • Green Lantern comics are frequently dominated by the Guardians and Lantern politics rather than heroics.
  • A lot of later Marvel Family stories are more about the Wizardnote  and/or the gods who empower Captain Marvel and less about the Captain himself.
  • In the Sonic the Hedgehog (Archie Comics), this happened when Knuckles' own series was cancelled and all of its characters and plots got reincorporated into the main book. As a result, for a time the comic was more about Knuckles than it was about its title character, until the excess characters were written out (one way or another) and the plot lines either tied off or more evenly merged with the main series.
  • Superman: In the Silver Age comics, Kryptonite went from a simple Achilles' Heel to a rainbow of radioactive rocks that could do anything, and was present in ludicrous quantities. This was toned down in the 80's but was brought back in 00's storylines Public Enemies and The Supergirl from Krypton (2004). Lampshaded in an issue of Superman/Batman where Superman is almost accidentally killed because it was cheaper for a film company to use real kryptonite than to make a prop.
  • X-Men has dined out for years on the idea of prejudice against mutants - to the point where it is the major thread of nearly every adaptation and any attempts to even tone down "Mutant Hysteria" (much less eliminate it) have been swiftly written out. When it was first conceived, anti-mutant prejudice was based on fears of mutant supremacy: that mutants like Magneto would eradicate/replace normal humans as the next stage in evolution, especially since anyone's child could be a mutant.

    Comic Strips 
  • Few people realize that Beetle Bailey was originally about the title character attending college. Him joining the army (in 1951) was originally going to be just a one shot story. He was in college for only six months before leaving forever. In this case, it was (arguably) a change for the better since the military focus made it far more popular and commercially successful.
  • Blondie was originally about a flapper girl from the twenties of the same name. After the Great Depression hit, the focus of the comic turned to domestic comedy involving her marriage to her inept, comically-oversized-sandwich-eating husband, Dagwood Bumstead. Dagwood himself originally came from wealthy roots — to mark the shift in focus, he was disowned by his family and his wealth for marrying below his social class and thus had to enter the blue-collar working world that he was unprepared for while Blondie shifted from gold-digging flapper to responsible and caring matriarch.

    Fan Works 
  • That whole deal with shopping for Kagami's goldfish in Starbound stems entirely from a technicality that the author's beta-reader commented on in episode 15 of the source anime. To begin with, there initially weren't any real plans to involve Gyopi; the fish was only mentioned by virtue of canon.

    Films — Animation 
  • Disney tends to do this with love plots. Although they have started subverting and inverting this, most of the Disney movies, both canon and non, have some kind of love plot. Most of the time this isn't detrimental to the story, especially when the original work involved a love plot. However, sometimes it can become a Romantic Plot Tumor. For instance, at the end of The Jungle Book (1967) when Mowgli meets the girl from the village and follows her out of the jungle, it becomes sort of an Ass Pull, since that's not how any of The Jungle Book stories ended.
  • The animated adaptation of The Return of the King lampshades the expanded importance of the One Ring in between The Hobbit and the The Lord of the Rings trilogy (see the Literature section) in "Frodo and the Nine Fingers":
    When Bilbo found that shiny ring
    In Gollum's cave of gloom,
    He never thought that it would turn
    Into a ring of doom.

    Films — Live-Action 
  • Star Wars has several examples.
    • It can be argued that lightsaber combat qualifies, as it was never paid that much attention in the original trilogy (only one actual duel per film, though after A New Hope they served as the climax for Luke's story in the film) compared to the prequels - and in the Expanded Universe, there are seven forms of lightsaber combat, each explored in detail, plus another unrelated set of three in some video games.
    • Boba Fett — starting with a non-notable background character with almost no dialogue, whom the audience liked for his "cool" armor, and ending up with the Mandalorians, an entire Proud Warrior Race like him, who have played a major role in at least two galaxy-spanning conflicts to date and basically became the Star Wars answer to the Klingons (not to mention the original source of the stormtroopers!). This case is somewhat unique in that much of it was the responsibility of a single writer who became a little too enamored with the Mandalorians and wrote about them at length (at least with the upshot that, thanks to that writer, there actually were Mandalorians other than Boba Fett in post-Original Trilogy stories).
    • The Star Wars video games, having a relatively limited amount of iconic canonical material to draw on, have become almost comical in the way various memorable elements of the movies show up over and over again in different, unrelated games. For instance, in the old "Legends" continuity, there have been at least seven different sets of Death Star plans that have been stolen seven different and mutually exclusive ways by seven different heroes or sets of heroes. Even when most of those were declared non-canon before the Legends declaration, there were still at least two versions of how each half of the plans were stolen, both featuring entirely different people doing the work.
      • It's notable in that, for a period of time, the games were generally consistent with one other (besides the above), where if something appeared in one game it would look the same as it did if it reappeared in another - when games started getting licensed out to other developers was when they took their own spin on locations and plots and nothing really matched up anymore.
    • See also how, thanks to the video games' endless reliving of the Battle of Hoth after its depiction in the video game for Shadows of the Empire, what was, in the movies, a one-time, fairly cool longshot that happened to pay off - the snowspeeder managing to trip an AT-AT with a tow cable - has now become the de rigeur, recommended means for killing AT-ATs.
    • The final battle around the droid control ship above Naboo in The Phantom Menace was a more low-key instance of the same thing as happened with Hoth. In the film, Anakin lucks his way into piloting a starfighter inside the ship and shooting at things until he does enough damage that it starts to blow up from inside. No less than two video games came out in as many years after the film - Battle for Naboo and then Starfighter - wherein the player character is someone also present at the battle, who also flies inside the control ship and shoots up enough things that the whole thing starts to explode - none of which are aware of any of the others.
    • Force Lightning is used six times in the six movies — three times by Palpatine (Return of the Jedi, twice in Revenge of the Sith) and three times by Dooku/Darth Tyrannus (all in Attack of the Clones), both major league Sith Lords. In the games, anyone who has a smidge of Dark Side can throw lightning around with impunity, and on a vastly greater scale, too. This at least does get touched on in one of the novels starring Jaden Korr, the protagonist of the Jedi Academy game that screenshot comes from, where it's noted that the ease with which he is able to call upon powerful Force Lightning, particularly when he's stressed, is a major source of worry for him even a couple decades after his introduction because in canon such abilities still tend to be the trademark of major-league Sith.
    • Hoth is an utterly unremarkable, nigh-uninhabitable snowball of a planet whose sole significance was a major Rebel base built there specifically because it's the last place anyone would look. And yet almost every Star Wars game since Shadows of the Empire features a Hoth level. Which would be excusable if the game, like SotE, were set during Episode 5 or between it and 6 — most are not and shoehorn in a Hoth level anyway! Star Wars: Rebel Assault and a trading card game tie-in to Star Wars: Galaxies even ended up retconning in another two battles on the planet in as many years before Empire, the Rebels apparently thinking the Empire wouldn't expect to find them on a planet where they had already found them two times before.
      • It gets to the point that, in Jedi Knight: Jedi Academy, when Luke is sending characters out to investigate whether the bad guys (a cult trying to resurrect an ancient Sith Lord) have absorbed strong Force auras from various planets, he's more certain that the player character, Jaden, will find them on Hoth because of that ten-second vision of Obi-Wan from Empire than he is of Rosh finding them at the remains of Byss, a planet that had actually been described in other works as being totally corrupted by the Emperor's dark side energy. That said, this case seems to get some Lampshade Hanging - when Jaden goes to Hoth and doesn't sense any aura, his first assumption is that Luke was wrong about it having one in the first place, and the cult's visible success from the excursion instead comes from salvaging the old Echo Base flight logs that lead them to other planets which do have strong Force auras - namely, Dagobah, which was established as having one even in the original movies (being able to mask his presence by it being the whole reason Yoda went in hiding there). Conversely, when Jaden later accompanies Kyle to Byss so they can finish Rosh's mission, they realize right away there's no aura there because it has been drained already.
      • Lampshaded in Star Wars: The Old Republic, where during the Hoth mission, the player states s/he has never heard of the planet. The Republic, apparently, is only there to salvage wreckage from a battle which happened to occur nearby... and the Empire's agenda is tying up Republic forces by forcing them to fight over a meaningless iceball.
    • Similarly, it seems everything visits Tatooine, which was introduced as the middle of nowhere. To be fair, while Tatooine is rather far out on the Outer Rim of the galaxy, it is also universally described at being directly near the intersection of four different trade routes, bringing many people there. And a combination of being controlled by organized crime and most of the planet outside the few big settlements being featureless desert that is also Tusken Raider territory (to say nothing of the various other predators we don't get much of a glimpse of, like krayt dragons) justifies its allure for underworld players like smugglers and bounty hunters, while for regular folk it remains an unimportant dust ball.
    • Cutting off arms and hands is a running theme in the films. In the Expanded Universe, it's given a whole backstory about how it's considered a traditional display of lightsaber skill. There's even a catalog of different versions, each with a different name.
    • At the end of Return of the Jedi, we see Anakin's spirit standing alongside those of Yoda and Obi-Wan, meaning he achieved spiritual redemption. There is no indication leaving the Dark Side amounts to anything more. A Karma Houdini, maybe, but at least there is no indication of it going beyond the Karma — in both the Legends and Disney continuities, he's still remembered pretty much solely as the ultimately-evil Dark Lord of the Sith. For absolutely everyone else in EU material, going back to Light (assuming it doesn't lead to their death) seems to give an instant legal amnesty and a clean slate, no matter how many billions they may have murdered in cold blood beforehand. Arguably justified in that the Force is indisputably real in the setting (not that this stops people from disputing it, even in time settings where Jedi are everywhere), and at least for Force-users, moral alignment actually is a concrete and testable thing. On the other hand, the setting also has many examples of Sith who are successfully able to disguise their alignment.
    • In The Empire Strikes Back, carbon-freezing a person was an improvised and experimental procedure applying an industrial freezing process to a living person; nobody was sure it was survivable, which is why it was being tested on the less-valuable prisoner, Han. In the expanded universe, it's a common imprisonment/preservation technique, even more common in media set before the original trilogy than after. This has reached the level of sometimes showing entire armies being hidden away in suspended animation for millennia.
  • The Invention of Lying: The movie is a comedy until it turns to the serious and heavy question of religion when Mark invents the concept of heaven to comfort his ill mother.
  • The Man from Earth: After the discussion of John's immortality turns to religion, a religious plot tumor ensues. Characters stops asking about his experiences as a 14,000 year old being and the discussion swerves to an argument about religion and mythology.
  • Played for laughs in Monty Python and the Holy Grail: partway through, the movie cuts into a modern-day documentary where an historian is outdoors talking about the myth of King Arthur, and a medieval knight rides through horseback, killing the lecturer with his sword. Several cuts are made over the course of the rest of the movie to the police investigating the crime scene and questioning his wife (despite this supposedly being set around Arthurian Legend), until eventually, the obvious climactic final battle is interrupted less than a minute in by a massive police force moving in and arresting everyone, at which the movie abruptly cuts to black. There's not even any closing credits, as the people responsible for them had been sacked over the opening credits.

  • The Holy Grail in Arthurian Legend grew to be the entire raison d'être of the Arthurian Court, taking on aspects of various magic hamper/magic mill myths, and creating a mythological snarl whose origins modern scholars are nowhere close to deciphering.
  • J. R. R. Tolkien:
    • When Tolkien was writing The Hobbit, he was also designing the fantasy world of Middle-Earth in his spare time, just for fun. For his own amusement, and to flesh out the world of The Hobbit a little more, he put a few references to Middle-Earth into the book, but he wasn't seriously thinking about adding hobbits to his private world-building project. However, when he decided to write a sequel to The Hobbit, the Middle-Earth references increased exponentially, to the point where the book (The Lord of the Rings by name) was as much a sequel to The Silmarillion (at that time unpublished) as it was to The Hobbit. Some massive amounts of retconning were needed to make the two stories fit into the same setting.
    • The One Ring (and Gollum). In Tolkien's first version of The Hobbit, Gollum willingly handed over the Ring to Bilbo as a prize for besting him in the riddle contest, it was just a plot point to give Bilbo the invisibility powers. Tolkien had to back and make Gollum far more sinister and un-sportsmanlike about the whole thing AND add in that he freaked out about losing the Ring, considering that in The Lord of the Rings, the importance of the Ring has swollen so much that the story pretty much entirely revolves on the corrupting power of the One Ring and Middle Earth is inadvertently saved because of Gollum's need to have his precious.
  • In Honor Harrington, Manpower Incorporated, a genetic slavery organization, was originally a minor background detail, with the focus of the series being on the increasingly escalating war between the protagonist Star Kingdom of Manticore and the antagonistic People's Republic of Haven. Starting around the tenth book in the series, however, the Mesa system, which is both home to and arm-in-arm with Manpower, became the Big Bad of the story. The shadowy cabal that controls Mesa was eventually revealed to be closing in on the end of a centuries-long plan to control the known galaxy via long-term political and military manipulation of every other government, all so they can reintroduce widespread genetic engineering to the galaxy and eliminate any opposition to it.
  • The concept of "phylotes" aren't even mentioned in Ender's Game or Speaker for the Dead. They go on to be the element that most of the story revolves around late into Xenocide and Children of the Mind.

    Live-Action TV 
  • Star Trek across its many incarnations and writers has had a lot of these.
    • The "Brain Bugs" from The Wrath of Khan went from a moderately small concept to a much larger one as successive generations of fans got a hold of the writing jobs. Incidentally, "Brain Bugs" is sometimes used as an interchangeable term for Plot Tumors; whether or not this is influenced by Wrath of Khan is up for question.
    • The Jefferies Tubes started out as fairly realistic maintenance tunnels that the odd tool or piece of equipment were in. This is realistic because sometimes with complicated engineering not everything is within arm's reach. These mutated over generations to labyrinths of tubes where everything important was kept — Fair to say no engineer would design something this malevolent.
      • The Star Trek: Voyager episode "Macrocosm" lampshaded this when Janeway gives the Doctor a rather complex set of directions through the tubes and the Doctor asks who designed the ship.
      • Parodied and lampshaded in Galaxy Quest.
        "Whoever wrote this episode should DIE!"
    • The Borg started out as technophiles who were only interested in stealing interesting technology and ignored life forms unless they became a danger, but they gradually mutated into Night of the Living Dead-style zombies. The first trip aboard a Borg Cube showed that Borg reproduced naturally and put implants into their infants. Meanwhile Picard was chosen to become Locutus as a mouthpiece for the Borg to announce their intention to conquer and enslave humanity. By First Contact, they were able to assimilate on the fly, injecting nanites directly into people to begin the assimilation process (though full assimilation was more involved). By the time Voyager encountered them, they were primarily interested in assimilating life forms regardless of their technological level, and eventually the Borg were revealed to be unable to actually understand anything without assimilating it.
    • The Vulcans have also gone through this. One of the complaints about the Vulcans on Enterprise was that they were portrayed as capable of deceit and underhanded behavior, the complaints arising because people took one character, Spock, who was in fact notably atypical, and used him as the archetype for an entire species. However, when you look at how Vulcans were portrayed in the canon, you saw Vulcans acting in quite un-Spockish ways, even as far back as his "wife" in the original series who manipulated things to get out of her arranged marriage.
    • Transporters were created as a last-minute cost-cutting cop-out to prevent expensive effects shots of shuttles landing on planets, but soon became a rich source of plots, with whole episodes centered on the zanier aspects of their operation, even though the unintended applications make them outrageous and are best ignored to begin with. See Misapplied Phlebotinum.
    • Perhaps the biggest one was the way the Prime Directive grew in importance until Enterprise was doing an episode where the only moral thing to do was to stand by and let an entire species of advanced, peaceful aliens die out when you could easily save them. Worse, the Prime Directive didn't even exist at the time that series was set. That species was allowed to die out because the character had somehow got it into his head that "evolution" is some kind of omniscient God who must not be disobeyed.
  • Doctor Who has a couple of examples.
    • The Cybermen's allergy to gold went from "could be choked by powdered gold dust" to "tossing a gold coin at them is like shooting Kryptonite bullets". When the new series reintroduced them, this tumor was quietly excised. Supplemental material mentions that the allergy to gold was discovered early in the Cybermen's R&D process and eliminated then. And then brought back in a new series episode, where a golden ticket temporarily disables a cybernetic implant capable of overpowering the Doctor himself.
    • In the sonic screwdriver's original appearance in "Fury from the Deep", and later in "The War Games", it was used for unscrewing things. It only gradually became a do-anything device. It was actually written out of the show because it was becoming a Deus ex Machina, before being reintroduced for the Eighth Doctor... and becoming a deus ex machina again. It got so bad that they had to introduce a second deus ex machina ("deadlocking") to counteract it. And now it doesn't work on wood either.
  • On the second season of Grimm, Juliette's amnesia and subsequent relationship and mental health issues became the B-plot of the entire season, which was odd, since she was a relatively minor character in the first season. Some found it incongruous, because the show is otherwise mostly about magical creature-people, their society and how they interact with (and sometimes threaten) humans.
  • When Ellen DeGeneres came out of the closet, her character on her sit-com, Ellen, did the same. It had been stated that the show would continue normally and that her being gay would not take over the show. However, in the fifth and final season, half the episodes focus on it. TV Guide wrote an article about this with the headline "Yup, She's Too Gay."note 
  • The surreal comedy episodes of The X-Files became the series' plot tumour in the sixth season especially. Whereas previously there'd been two or three per season that were refreshing escapes from the show's usually dark and disturbing subject matter, it was a bit much to get a silly comedy episode every single week. (The other perspective was that this was a relief from the conspiracy arc that didn't seem to know where it was going, but that's a matter of fan opinion.)
  • Archie Kennedy in Horatio Hornblower became a rather inconvenient character-flavored plot tumor (and nearly a Romantic Plot Tumor if you squint) as a minor character cobbled together from several bookverse extras and who proceeded to swell vastly in importance as the highly non-canon best friend of a hero not known for having extroverted besties. Was forcibly excised when the Forester estate demanded that the character be killed at the end of the 6th film in order to refocus the film series on an appropriately introverted Horatio.
  • Due to Executive Meddling, Writing by the Seat of Your Pants and a host of other factors, the second season of Twin Peaks ended up being dominated by several inconsequential storylines that had originally been planned as minor subplots or filler - the Miss Twin Peaks pageant, the adoption of Nicky, and so on.

  • In the original play Chicago, Roxie merely mentions vaudeville as what she intended to do after getting out of jail. In the musical, vaudeville is the lifelong ambition of both Roxie and Velma, and every musical number has a vaudeville motif. Women who murdered their husbands for cheating only became a major subject in the musical, which not only added the "Cell Block Tango" but completely rewrote one minor character who appears later to fit that theme.

  • Pretty much every single Transformers series since about 1992 where Takara (the Japanese toy company that shares the rights to the Transformers brand with their American partner Hasbro) had a major say in the direction of the toyline/story development has over-emphasized the role of Convoy/Optimus Prime and his derivatives. This is particularly glaring in short-lived toy-only lines with no television show to back them up, which will often start with a new Convoy toy... then maybe a different character as the second toy if they're really lucky, or another Convoy-related toy of they're not so lucky... and then the line ends and gets replaced by a new line that starts with the next Convoy all over again. The most noteworthy example would be the "Robot Masters" line from 2004, which, during its 25-toy-run, had no less than seven toys with the word "Convoy" in their names (including redecos). One of these "Convoy" toys was even a retool of a Megatron toy and was intended to actually be a form of Megatron.
    • Hasbro is far from blameless in this category, mind you. In the early days, there was really no implication that Optimus Prime was anything more than a charismatic military leader (in the Marvel comics, he wasn't even the leader of the Autobots as a whole, just the army), and it was shown that his role could pass to others. After significant backlash from Prime's death in The Transformers: The Movie, Hasbro pretty much locked in the idea that Prime was the only character who could be the leader, and escalated his personality from "decent chap" to Messianic Archetype. Frequently, it would be introduced that "Primes" represent some kind of higher lineage, with Optimus either being part of a dynasty or a straight-up reincarnated deity.
    • A more notable example in the Transformers mythos: The Autobot Matrix of Leadership. The term "matrix" originated with Optimus's "creation matrix" in the comics, in which it was simply used to create new toys. It was then introduced into the movie with its current title, serving only as a MacGuffin to defeat Unicron (note that prior to Unicron mentioning it, Megatron had absolutely no use for it); it quickly became the central do-anything power source and all-purpose MacGuffin for the cartoon, and was even declared to have some of the essence of the Transformer god Primus. Several series have even had Megatron and other Decepticon leaders dip into Motive Decay by having them all lust after the Matrix. In All Hail Megatron, Megatron's acquisition of the Matrix was treated as "game over" for the Autobots, and Starscream was able to win over the entire Decepticon army just by possessing it.
    • For that matter, the Primus/Unicron conflict. In G1, Unicron was "merely" a humongous planet-devouring Transformer, who got defeated in the very movie he appeared in. Eventually, however, he was retconned into a "multiversal singularity" existing in every Transformers continuity at once, and gained a Good Counterpart, Primus, who showed up initially in the Marvel comics before being added into just about everywhere he could be fit. Eventually, fans got so sick of Primus and Unicron that Transformers: Animated very pointedly avoided mentioning either of them, and post-Animated material tends to range wildly on how important they are—works based closely on the Aligned continuity tend to make the whole conflict relatively important, while works based more closely on G1 tend to ignore it as much as possible.
    • Sparks. They were a creation of Beast Wars; nothing in G1 pointed to the idea that an actual object was required to keep a Transformer operational, any more that one normally would for a machine. The Dinobots and Combaticons were built on site with no access to any "life-giving" entities, the Stunticons and Aerialbots were animated by Vector Sigma, and Optimus Prime was simply repaired into full working order by a random Quintesson after dying (twice, at that). By the time of the movie and Animated, the BW idea of sparks firmly secured their place in the mythos, to the point of postulating that all Transformers were creations of the AllSpark.

    Video Games 
  • Neverwinter Nights 2, starting with the Ember Trial, seems to force one quest on the player after another, leading to the question "Whatever happened to going to the Jerro Estate?". It takes most of part II for the answer to that question.
  • Monkey Island:
    • The Insult Swordfighting in the first game was meant to be a parody of the witty banter found in high adventure movies, but by the time Escape from Monkey Island came around, there's apparently an Insult version of nearly every sport available floating around the Tri-Island Area. May have something to do with the legendary Ultimate Insult, an insult in primordial (read: monkey) tongue that burrows into the heart of a person's psyche and completely obliterates it. It turned Lechuck into a cringing, primal ape! Basically the true secret of Monkey Island.
    • Escape also included The Reveal that Herman Toothrot is H. T. Marley with Easy Amnesia.
  • Sometimes the earlier games in The Legend of Zelda series seem to be set in an almost separate universe than the more modern ones:
    • Originally, the Triforce was a mysterious triangle that granted magical abilities, and there were only two of them, not three. Come The Legend of Zelda: A Link to the Past, however, and it's the Cosmic Keystone of the entire Zelda universe with omnipotent wish-granting and reality-warping powers. The significance of the Triforce mark was also different. From The Legend of Zelda: Ocarina of Time onward, the Triforce mark on one's hand signified which piece of the Triforce one had and would glow when its power was being used. The first appearance of this mark was in Zelda II: The Adventure of Link, and it showed up on Link's hand before he even had the Triforce of Courage. It just marked him as the hero destined to claim it.
    • The Master Sword being the only sword able to kill Ganon is a relatively recent idea. In its first appearance in A Link to the Past, the Master Sword was a powerful weapon to defeat evil, but in order to kill Ganon you had to stun him with the Master Sword, then actually harm him with a Silver Arrow. After Ocarina of Time the relationship has been reversed, and the Light Arrows are needed to stun Ganon so you can harm him with the Master Sword. Sometimes you don't even need the arrows at all. The Master Sword meanwhile has been given increased importance, and it's a Cosmic Keystone just as important to the world of Hyrule as the Triforce now. Although, in Ocarina of Time, it was required only to seal him away; you're able to harm Ganon with the Biggoron Sword. Skyward Sword gives us the explanation that Ganon is empowered by the curse of the demon overlord Demise, and the only thing that always works is the very weapon that killed Demise. This was toned down in Breath of the Wild, where while hyped as "the blade that seals the darkness" in flashbacks and very powerful in-game, it isn't actually required to defeat Ganon.
  • Metal Gear:
    • The games were once about bipedal nuclear tanks but ever since Metal Gear Solid 2: Sons of Liberty introduced the Patriots, everything, even retroactively, has something to do with them.
    • In the earlier games, Unusable Enemy Equipment was handwaved by the fact that the weapons were keyed to their users via Nanomachines and won't function for anyone else.note  In Metal Gear Solid 4: Guns of the Patriots, the entire plot revolves around the weapon-identifying nanomachines (hence the subtitle) and the computer system that regulates them. Ironically enough, this is also the game that introduces the ability to take weapons from their keyed users and unlock them for your own use.
    • By a certain scale, nanomachines started to be responsible for basically maintaining the entire modern world order and were probably intended to be used eventually on every civilian in the world along with government officials. The Patriots as of the events of MGS2 were even revealed to basically just be the AI system regulating said nanomachines, with the original human ones being reduced to psychotic messes (Ocelot), rebel leaders (EVA/Big Mama), persistent vegetables (Zero), or just plain dead (Para-Medic/Dr. Clark and Sigint/Donald Anderson).
  • The Cerberus group in the Mass Effect series. Initially it was just a shadowy organization with a few bases operating on uncharted worlds, with substantial influence but no indications of connections to major plots. Come Mass Effect 2 they're a central part of the plot, and in Mass Effect 3 they're a major military power capable of seriously challenging the Alliance and sabotaging the war effort against the Reapers. They also form a central role in three of the four Expanded Universe novels.
  • Aku Aku in the first two Crash Bandicoot games was just a silent benevolent spirit in a mask that provided the hero protection and temporary invincibility and had absolutely no relevance on the plot. Come Warped, Aku Aku's role is expanded as Crash and Coco's mentor, he's finally speaking and his Evil Twin Uka Uka is introduced, to whom former Big Bad Cortex is Demoted to Dragon. Not only did it contribute to Cortex's Villain Decay but it also derails the plot in further games into a strife between two opposite gods in which both Crash and Cortex are pawns. Further, in the original game's manual, the masks were protective amulets that Aku Aku made and distributed over the islands, while Aku Aku himself was a spirit who used to be a human witch doctor; now, he is the mask, and by the time of Crash: Mind Over Mutant, he speaks like his entire family has always been masks.
  • World of Warcraft:
    • Prior to the game, the Old Gods' role in the main story lines was minimal at best; it was known they existed and had a significant impact on the setting, but were a footnote compared to more immediate evils such as the Horde, the Burning Legion, and the Scourge. Come the MMO however, and their role has expanded exponentially each expansion as the already existing antagonists are systematically killed off, to the point that by Cataclysm, they were basically the main antagonists alongside Big Bad Deathwing, and in Mists of Pandaria, their influence is what caused the creation of the Sha (the evil beings that are antagonizing the continent and whose power is harnessed by people such as Garrosh to fuel their plans). The Chronicle books finish this transition by establishing a Myth Arc for the franchise that revolves around newly-introduced masters of the Old Gods, the Void Lords (themselves a tumor that started out as mere voidwalker leaders), being the ultimate Greater-Scope Villain (beyond the Old Gods, who already had that role) for the entire franchise (even to the point of being revealed to have caused the Face–Heel Turn of the previously established Greater-Scope Villain, Sargeras of the Burning Legion).
    • One can argue that the constant conflicts between the Horde and the Alliance is this. During classic and The Burning Crusade, the bouts between the two factions was largely just proxy cold-war battles, which according to Word of God, had little to no relevance to the overall story. Then Wrath of the Lich King was released, and the writers apparently decided they wanted to kick the conflict into high gear and make it a major storyline element. Cue WotLK and two following expansions having storylines that were constantly sidetracked by the Horde/Alliance war (even when it made absolutely no sense for the factions to be warring at the time, like usually more level-headed characters starting a fight on the doorstep of a villain who can turn their dead against them). By Mists of Pandaria, it had completely derailed the overall storyline, and most of the playerbase had gotten sick of it all. Early Warlords of Draenor development initially tries to avoid any storyline hooks or references to the recent war, but then apparently underwent Aesop Amnesia with Ashran, with the Horde and the Alliance being at each other's throats again. Legion mostly avoids it in the main plot, but still comes up with a contrived reason for the factions to distrust each other during an apocalyptic invasion (the Horde is forced to retreat when the flank is overrun, but completely neglect to communicate this to the Alliance, who believes they were abandoned on purpose). Battle for Azeroth has the faction war become the main storyline from the start.
  • Alone in the Dark: Burning the Evil Roots (of an Evil Tree, of course) in the 2008 game. Padding at its best. A nod to the original game, where the Final Boss is an evil tree that must be burned.
  • Ace Combat ended up with two starting from the PS2 games. After Ace Combat 3: Electrosphere, the story began working its way back up from the modern day to the projected future seen in that game... which was soon almost completely derailed by the combined aftermaths of the Ulysses asteroid from the backstory of 04 and the Belkan War alluded to in 5 - to the point that the sixth game had the bad guys inspired by both (economically crippled by the impacts of asteroid fragments, then brought together by a faction using Belkan technology). And after that, when it finally seemed like those two events had inspired everything they could and the devs had no choice but to make an actual sequel or prequel to Electrosphere, for the next decade the series almost entirely switched over to alternate continuities set in the real world, or remakes that mostly retconned the Belkans into being responsible for everything else that had gone wrong across the series before then.
  • Pokémon:
    • Legendary Pokémon started out as powerful, one of a kind Pokémon that could be fought and caught but had nothing to do with the storyline of the games. Gold and Silver made them actual mythological creatures that where tied into the backstory but you still did not need to fight them, then Crystal required you to fight one of its legendary Pokémon several times as part of the story. By Ruby and Sapphire every single villainous team has tried to use the mascot legendary in their plans and a couple more legendaries often have a plot important role; even the remakes of Gold and Silver made it a requirement to fight your game's mascot legendary as part of the story.
      • Pokémon Sun and Moon does subvert it, since most of the villains' focus is instead on Cosmog and the Ultra Beasts. It subverts it by revealing that Cosmog actually is the version legendary, just in a harmless baby form, and none of the characters actually knew it. Given her dismissive attitude once she's done using it for her plan to summon the Ultra Beasts, and the fact that she planned on capturing the version legendary for her collection, it's easy to assume even the villain didn't know what Cosmog really was.
  • The Ravenhearst story-arc from Mystery Case Files could have been wrapped up as soon as its first game finished, and yet the story got developed more and more through all the subsequent installments, going more insane with every game. Somehow, between Ravenhearst and the arc's final wrap up in Ravenhearst Unlocked, only Shadow Lake and the non-PC games weren't connected in any mean to the Ravenhearst storyline — 10 games in total (Dire Grove and 13th Skull being only loosely linked, though). In other words, the story of a woman being abducted by a jilted lover ended with the lover's 500 years old father unearthing his cursed medieval hometown with the help of a carnival owners crystal ball after spending 500 years as a druid, a dark sorcerer and murdering hundreds of innocents in his quest for immortality. Phew!
  • In the Nasuverse, Servants, and the Holy Grail War as a whole. In the original visual novel, Fate/stay night, Servants were pretty clearly supposed to be a one-and-done concept in an already-vibrant Urban Fantasy world, an oddball ritual carried out by declining mage families. There were only five Holy Grail Wars, all of which were separated by anywhere between decades and centuries, and all were failures. And the one featured in FSN is the last one, with the characters going out of their way to make a sixth War impossible. But, as it turned out, Servants ended up being a very adaptable concept, and FSN ended up being very popular, which led to a prequel focusing on the Fourth War. Then an alternate universe involving the local equivalent, the Moon Cell War. And another alternate universe with its own War. And another. At this point, the Fate side of the Nasuverse has gone from being its own small, rather limited corner to being the central axis upon which the world revolves.
  • Your main adventure in OMORI focuses on finding Basil after his disappearance, but the party keeps getting sidetracked by other goings-on which can all be traced to Sweetheart's antics, both on- and off-screen. It's eventually implied that Omori intentionally made Sweetheart into this role, to keep the party distracted from finding Basil and learning the truth.
  • The current page quote comes from Soul Nomad & the World Eaters, as Revya's group keeps getting continually side-tracked from their mission to find and end the threat of the titular monsters. Turns out it was deliberate, as one of your party members, Levin, is actually controlled by the last of the World Eaters, Raksha, and each side-mission is part of Raksha's plan.
  • When Summoning Magic was introduced in the third installment of Final Fantasy started out as just another type of magic that, originally, had the advantage over regular Black Magic when it came to targetting groups of enemies, with some creatures needing to be beaten in battle before they'd lend you their power. Final Fantasy VI was the first installment that made them central to the plot of the game. From there on out, with the exception of Final Fantasy VII all following installments made Summons central to the plot in one form or the other. On the gameplay side they often came to be treated as a special mechanic, with a particular extreme case being Final Fantasy VIII where stat growth and ability-, and magic use relied on characters equipping the various summons found during the plot and in sidequests.

    Visual Novels 
  • Melody:
    • Exaggerated with Melody’s career after her tutoring sessions are over. The developers originally wanted to limit number of updates to half a dozen (coinciding with the duration of Melody’s summer in game time), but they realized that it only would make sense to continue to give Melody a believable entry into the music industry, doubling the length of the story.
    • Xianne was only meant to appear at the karaoke bar originally, but she was given a larger role in the game at the requests of some fans, becoming a love interest of the protagonist and Sophia.

    Web Animation 
  • Discussed in the Terrible Writing Advice episode "Plotting a Story".
    Beaubien: We could add a subplot that goes nowhere! Adding a subplot to the story that is a natural outgrowth from the main plot and merges seamlessly to the final climax can work, but by this point, I'm getting sick at looking at the main plot. I think I'll become enamored with my subplot and let it take over the story!
  • The Freelancer program of Red vs. Blue began simply as independent soldiers who worked for the paying side and to introduce the AI programs. The mini-series Out of Mind expanded this to being a special program to combine AIs with soldiers and the AI revolt. The Recovery One and Recollection trilogy further expanded it to be not only a program designed to win the great war with unscrupulous methods, but the cause of the Red vs. Blue war and all the events of the first five seasons as an extended Freelancer training scenario. Finally, the ninth and tenth seasons had the plot equal parts silly comedy and the darker Freelancer backstory.

    Web Comics 
  • Sluggy Freelance has had a couple of these, thanks to being Kudzu Plot incarnate.
    • The Dimension of Pain was originally just a concept that fueled roughly a week's worth of strips. Then Pete Abrams decided to make it a Running Gag, having the Dimension of Pain demons show up each Halloween to claim Torg's soul. Each Halloween arc got longer than the last, and eventually the demons caught on so much that they were made the stars of their own B Side Comic Strip "Meanwhile in the Dimension of Pain." Then eventually even that wasn't enough, and the Dimension of Pain demons became the main antagonists of the massive "That Which Redeems" arc. Pete Abrams has, however, stated he knew the demons would be invading the Dimension of Lame when he left them a potential means to do so, right in the first story.
    • There's also Bun-bun's grudge against Santa Claus. At first there were just a handful of strips around Christmas each year where Bun-bun would try (and fail) to kill Santa Claus. The feud kept escalating, however, with more and more side characters (the Easter Bunny, Santa's black ops elves, aliens with a weakness against Nerf) getting involved, until it eventually exploded into Bun-bun amassing an army and going on a holiday killing, world conquering rampage in the three month long "Holiday Wars" saga (which itself launched the even longer "Oceans Unmoving" arc).
    • Both of these Plot Tumors, however, seem to have been successfully removed. The Dimension of Pain has not been seen for years, ever since "That Which Redeems" concluded. And, while Bun-bun still makes the occasional attack on Santa Claus, holiday figures and black ops elves have long since ceased to play a prominent role in the story as of the comic's twentieth anniversary.
  • Concession started off as a comic strip about a bunch of anthropomorphic characters who worked at a concession stand at a movie theater (The author actually based it around the stupidity he experienced, working in customer service is a good way to get material for comic strips). But in the later'll not really see that much about an actual concession stand. For awhile, the actual concession stand was more or less put to the side, and until it got wrapped up in the massive Plot Tumor, it didn't even play a role beyond the occasional appearance of a main character who was still employed there. Immelmann has actually admitted that it's only about concession stands In Name Only and centers around the character Joel and his plot. It even says so right in the "About" section.
  • In Sam & Fuzzy the original comic was mainly a slice of life style that was mainly a gag a day style. Then ninjas were added. And a demonic refrigerator. After that, things got weird. Now the whole story revolves around the weirdness and the weirdos and pretty much every arc has ninjas in it due to Sam becoming the Ninja Emperor.
  • The "Patriarchy" in Sinfest during fall of 2011 quickly grew to overtake the strip, turning the focus to the actions of Xanthe (AKA "Trike Girl") and the ramifications of said actions on the world. Sinfest runs into this trope a lot, due to the author writing by the seat of his pants. "Patriarchy" is notable for taking over so much in such a short time period, but there are plenty of other examples:
    • Possibly the first was the Devil's "crisis of faith", which spun so far out of control that the author didn't know how to end it. Big D was AWOL for several real-world months before it was revealed that he just went on vacation.
    • The "Reality Zone" was introduced for a one-off Sunday strip, then became a recurring plot element.
    • A 2010 storyline had Squig becoming a hobo and Walking the Earth meeting all sorts of weird cameos, eventually winding up lost in a desert and pining for home. The author was eventually able to tweak an unrelated storyline to get Squig home.
    • And The Fuschia/Criminy subplot, which became the strip's chief attraction for awhile before the Sisterhood/Patriarchy conflict came to the forefront.
  • The trolls in Homestuck could be considered this. Most fans don't even remember that they didn't appear until Act 3 and they were retroactively added into the earlier story through flashbacks.
  • The same thing happened in Problem Sleuth, the comic to which Homestuck is a Spiritual Successor — originally, the imaginary world was just a side-thing used to solve some puzzles, but eventually the action moved there entirely to the point where it was hard to remember that it wasn't really real.
  • The character Benni and the topic of child sexual abuse have taken over Forest Hill. Benni first appears as an unsympathetic bully who sends Kaleb to the hospital, but he later reappears and it is revealed that he is being sexually abused by his father. This ends up completely taking over the comic as Benni becomes a main character and Flora decides to become his foster parent. And then Hunter gets sexually assaulted by a girl who is then revealed to be a friend of Benni's who is also being abused, and Benni reveals that there is a whole conspiracy of pedophiles in the town. The author of the comic has said that he never originally planned for the comic to go in this direction.
  • While ostensibly about its titular character, Sonichu rapidly began devoting more and more of its plot to a thinly-veiled retelling of events in the life of the author, Christine Weston Chandler. By around the fifth issue, the plots focusing on Chris had more or less completely taken over the storyline, resulting in the series bearing a reasonably ironic Artifact Title, and Sonichu becoming a background character in his own comic!
  • Invoked in typically meta fashion in The Order of the Stick — Tarquin, Elan's Evil Overlord father, simply refuses to accept that he's merely a B-villain in the story, insisting that Elan is The Hero and overthrowing his father must be his primary goal in life... just as soon as he and his friends have taken care of this inconsequential cosmic-scale Eldritch Abomination nonsense. Even when Elan himself comes to the conclusion that defeating his father, while desirable, is less important than riding off to Save the World, Tarquin refuses to let the Order leave and makes repeated attempts to reframe the narrative in his favor. He's ultimately abandoned as a dangling plot thread, which he lampshades himself is "A TERRIBLE ENDING!" Ironically, his being left shouting that makes for a perfect ending from the perspective that the biggest conflict of this story was the fight against his seemingly iron grip on Narrative Causality.

Alternative Title(s): Plot Tumour, Brain Bug