Malignant Plot Tumor

"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!"

— J.P. Beaubien, Terrible Writing Advice

You are watching a movie, or reading a book and everything is going along swimmingly. There is an A-plot and maybe a B-plot and a C- and D-plot thrown into the mix too. While the storyline isn't too obvious, it's pretty clear that the climax is going to be with the Big Bad that is the focus of the A-plot. But there is also a small E-plot, it's so small you might not even notice it, but it's there, growing, waiting... and it strikes just as the other plots are gathering steam/nearing resolution. It has transformed from a tiny chrysalis to a hulking, immovable behemoth that plants itself squarely in the path of all the other concurrent plotlines. Its demands were not met, and now there will be consequences.

This is the Malignant Plot Tumor. A tiny sub-plot or event that happens in the background, something the characters don't notice or simply ignore to deal with more important matters, until it finally grows so out of proportion — much like a literal cancer cell — that everyone is forced to drop everything else to deal with the unprecedented threat. Unlike a Filler Arc that is simply meant to pad out runtime, the Malignant Plot Tumor has lasting consequences for the characters, reshaping or even completely dismantling the other plotlines if not handled in a tidy and timely manner. Say the heroes ignored a small-time crook because they were more interested in the Big Bad, only to find that crook has become a big-time crime lord that now owns the whole city and is out for their blood. Or the villains overlook that one loose domino in their scheme because they're so focused on the heroes, only for it to topple and collapse everything at the eleventh hour before the final battle can even begin. The readers may have caught these little loose threads, but the characters didn't, and now they have to confront the aftermath.

Despite its dire-sounding name, this trope can be used with excellent results. Ergo, you might even call some cases Benign Plot Tumors. Little problems being shoved under the rug, only to emerge much bigger and at the worst moment, is a tale as old as time after all. Done well it can add a pinch of realism to a story, and if the Tumor was something that could be dealt with easily in the past, it can teach the characters and the viewers An Aesop about not leaving loose ends untied.

Compare to a Plot Tumor, where the growth of one aspect above all others is unintentional, and Halfway Plot Switch, which is a far more abrupt version that lacks any lead-up and sometimes leads to a total Genre Shift. Romantic Plot Tumor is a specific version for romance subplots. A Porn Without Plot might develop one of these, transforming into a Porn with Plot, or even abandoning its pornographic aspect. See also Arc Welding. May overlap with the Hidden Agenda Villain who becomes increasingly menacing as more and more of their plan is revealed. Don't confuse with the Bait-and-Switch Boss, which is oftentimes entirely unrelated to plots and subplots.

WARNING: SPOILERS AHEAD

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Examples:

Anime & Manga

• The Chimera Ant arc in Hunter × Hunter started off as a side story, but eventually ended up ballooning to 132 chapters and lasting seven years real time because of numerous hiatuses.

Card Games

• In the Mars Attacks! bubblegum cards series, the Martians invade! And they release giant bugs to mop up humanity! And then disappear for most of the cards, as all but two deal with the giant insects until humanity suddenly decides to attack Mars for the last five.

Comic Books

• Valiant Comics' 1990s revival of Magnus Robot Fighter initially picked up right where the Silver Age series left off, with a decadent upper-class humanity becoming increasingly dependent on robots and vulnerable to antisocial ones; the robots chafing under humanity's rule and sometimes becoming extremely dangerous; the vast slums on the Earth's surface, beneath the gleaming towered cities, where life is terrible; and Magnus trying to find a way to set things right for all three factions. It had always been a cool premise with a lot of potential, and at first the Valiant title explored it in much more depth then the original Gold Key Comics version had. Then the Malev Robots from space invaded, conquering Earth and derailing all of the above-mentioned premise. All that mattered after that was everybody fighting space robots.
• Marvel Universe: Over the course of Donny Cates' runs on Venom, Guardians of the Galaxy, and seemingly culminating in King in Black, practically everything related to Symbiotes is shown to be connected to their dark god, Knull. At first, it seems reasonable, being their creator, but it gradually becomes apparent that his scope is far greater. His decapitation of a Celestial led to the creation of Knowhere, and his first symbiote was stolen by a man who became Gorr the God Butcher, both in his origins issue. His control extends to the Exolon worn by Wraith, retconned into being symbiote prototypes. This is expanded into "pretty much anything darkness-related" with the likes of the Void in King in Black.

Films — Animation

• In Futurama: Bender's Game, the titular game starts as Bender tries playing an RPG and his imagination goes overboard. However, this is but a loosely connected side-story to the main plot about dark matter (fuel). Then, right as that plot is reaching its climax, the messing with quantum physics caused the dark matter Bender had on his person to suddenly get sucked into his fantasy.
• For most of Wishology, the head of the Mecha-Mooks is simply a recurring opponent. However, after seemingly falling into the background, he suddenly goes rogue and absorbs the entire planet. With the revelation that Dark Is Not Evil, he proves the trilogy's true Big Bad. Considering all the parodies in said films, he is likely a direct Shout-Out to Smith.

Films — Live-Action

• The first half of Birdemic is a rather bland romantic comedy. The second half is a laughably bad horror movie with terrible CGI birds.
• The first part of The Birds is mainly about the romance between Rod Taylor and Tippi Hedren, which ends up completely drowned out by the titular bird attacks by the end of the movie. Most people only know the film for the bird attack portion, leaving them quite confused by how long it takes to actually get to it.
• In Charlie and the Chocolate Factory, this begins to surface as the tour is about to begin and it's revealed that Willy Wonka has a hard time saying the word "parents". Starting at about the halfway point of the film, the audience is privy to Flashbacks of his childhood that reveal he had a Fantasy-Forbidding Father who ultimately abandoned him alternating with the tour scenes. Finally, Charlie is the last kid standing and Mr. Wonka intends to make him his successor... and the plot tumor turns out to stand in the way of the novel's ending. Mr. Wonka reveals that a condition of his offer is that the boy abandons his family, as his traumatic childhood has led him to think that it only holds one back. Charlie must decline, and Mr. Wonka slips into a depression of sorts even as Charlie's family's fortunes improve without him. Finally, Mr. Wonka consults Charlie, who convinces him to reconcile with his father. Only then does the Happily Ever After of the novel commence.
• The titular fight in Godzilla vs. Kong is made out to be a huge deal that the previous three MonsterVerse films have been leading up to, even though the mere notion that Kong and Godzilla have any relevant relationship with each-other wasn't introduced anywhere in the franchise until the third film; and even then, it's only explicitly revealed that the two Titans' species were once rivals in the very last shot of that film's Creative Closing Credits.
• The Matrix: The later two movies in the original trilogy, Reloaded and Revolutions, seem to be about the showdown between the machines and free humans, but while those two sides are busy fighting, Agent Smith is busy replicating, and by the end, the warring factions must agree to a truce to deal with Smith. Almost a literal example, as Smith's replicating resembles the behavior of tumor cells a lot.
• Monty Python and the Holy Grail has a scene in which a modern historian explains the setting of Arthurian-era Britain, but then has his throat cut by a passing knight on horseback. Just another absurd gag in a movie full of them, except that we see cutaways to the police investigating the crime throughout the film. They show up at the end and arrest Arthur and his retinue for it, conveniently preempting a big final battle scene that the production didn't have the budget to stage.
• Cutler Beckett and the East India Trading Company in Pirates of the Caribbean. The company is more-or-less mentioned in passing in the first film, before becoming much more of a threat in the following two films. By the time At World's End rolls around, the combined threat of Beckett and Jones was enough to ultimately unite the world's pirate forces, who up until then were crossing and betraying each other on a regular basis.
• Many people forget that the first half-hour of Psycho is a heist plot involving Marion Crane embezzling money from her boss and making her escape. The entire plotline is completely abandoned once she's murdered partway through the film. The emphasis then transfers over to Norman Bates and how he's eventually captured.
• Red Eye starts out like a romantic comedy before revealing that the male lead is a Psycho for Hire here to present the heroine with a Sadistic Choice. If only the advertising campaign had understood this trope, it might've worked.
• The main plot of Stealth is about an AI fighter jet which goes rogue and attempts to start a nuclear war, with subplots about the military contractors who wanted to figure out how it gained independence and one of the other fighter pilots being shot down over North Korea and running from the army. Halfway through, the AI is persuaded into giving up, making the military contractors the main plot point, before that is resolved anticlimactically so that the climax can take place in North Korea. At the very least, the way the runaway AI is talked down involves a big emphasis on teamwork, which is brought up again in the in-universe justification for the pilots breaking ranks and embarking on the rescue mission to Korea.
• Touch of Evil spends much more time showcasing the war between Hank Quinlan (a Knight Templar Dirty Cop who frames any criminals he deems guilty with very little actual investigation) and Mike Vargas (a By-the-Book Cop who discovers how extensive Quinlan's corruption has become and tries to take him down) and extremely little showing the investigation of the bombing of a local captain of industry. The resolution to this case (that the man that Quinlan suspected and then framed really was the one who did it) is given in a single sentence in the last minute of the film, just to add an extra layer of irony to it all.
  Schwartz: Well, Hank was a great detective, all right.
  Tanya: ...But a lousy cop.
• The Village (2004) switches halfway through the movie from focusing on Lucius' trying to unravel the village's secrets to Ivy going on a perilous journey to find medicine before it's too late. The village's secrets are still revealed as a result of Ivy's journey, however.

Literature

• Codex Alera: The Vord are introduced in the first book as the nasty but apparently unintelligent and unimportant guardians of the MacGuffin of a Side Quest. In the second book, they prove to be very intelligent (though only collectively) and become a major threat, only to apparently be completely wiped out. In the fifth book, they're back with a vengeance, having been building up their forces massively in the background and forcing Tavi, the Canim and Lord Aquitaine to team up to stop them.
• Gentleman Bastard: The groups con of the Salvaras seems to be the A-plot of The Lies of Locke Lamora. The Grey King is mentioned only as a background menace but eventually becomes the Big Bad. The Salvara heist plotline is continued but is only important in how it related to the Grey King. Later books in the series make this plot structure more expected, with plotlines regarding heists and antagonists frequently intertwining.
• Henry Darger's autobiography The History of My Life begins with 206 pages of his early life, then digresses for 4,672 pages on a tornado nicknamed "Sweetie Pie". It's somewhat understandable, since he's referencing several actual deadly tornado systems he would have witnessed as a teen.
• The Lord of the Rings: The entire plot springs from a minor plot point (the magical ring found by Bilbo) in The Hobbit.
• Matter starts off apparently about a deposed prince gaining back his throne from the Evil Chancellor on a quasi-medieval planet, while more advanced aliens manipulate things behind the scenes. Then an archaeological dig is mentioned a third of the way through the book. Then later, the heroes find something in the city. Then with maybe four chapters left, the thing they find turns out to be Sealed Evil in a Can, whose first act is to kill all of the characters involved in the struggle over the throne. All but one of the surviving characters die trying to prevent it from blowing up the world.
• The Night's Dawn Trilogy (especially book 1) seems to be about smuggling, politics, and revenge. That is until, halfway through the first book, out of left field, the dead come back to life.
• Otherland involves a huge number of characters, and starts off rotating between their not-immediately-connected stories. The serial killer Johnny Dread is among this cast but doesn't play a particularly prominent role in the first volume. However, he grows in power and significance to be the main antagonist that everyone is fighting at the climax, even overshadowing the creator of the virtual world they're in.
• Perdido Street Station starts off looking light — the A plot is going to be a scientist helping a bird man to fly again, with a B plot of his girlfriend making a sculpture for a mysterious crime boss. But then one of the caterpillars the scientist was studying hatches and starts Mind Raping everybody. Everything else gets pushed to the side when it turns out that the moths are just about the deadliest thing in the world (even the Legions of Hell are scared shitless of them).
• A Song of Ice and Fire: The Night's Watch and their undermanned defence of the Wall initially seems, compared to the epic civil war in the South, like a pretty minor plot which we're only seeing because the son of a main character is up there. It gets a bit more interesting when the Others show up, and later one of the claimants to the throne decides to assist the Watch, but the sheer world-endangering Zombie Apocalypse nature of their threat is only gradually revealed to the reader and is still unknown or unappreciated by the vast majority of the characters. It takes the reader from rooting for whichever claimant they like the most to which one seems most able to defeat the Others.

Live-Action TV

• In Season 4 of 24, the raid on the Chinese embassy doesn't seem like a big deal at first, but wait until the end of season 5.
• In seasons 2 and 3 of The 100, we have a rather minor plot of Jaha looking for the City of Light while the main protagonists focus on surviving on the Earth and their issues and alliances with the grounders. When Jaha finds the City of Light at the end of season 2 and returns to the camp at the debut of season 3, he starts to recruit for his group. By the end of season 3, they are the main threat, with ALLIE — the AI that brainwashes them — as the Big Bad of the season, and all the protagonists must work together to defeat her.
• In Babylon 5, mysterious alien vessels are introduced about halfway through the first season. Their first appearance is in the appropriately titled episode "Signs and Portents". We don't even learn the name of the race that uses these strange-looking ships until after a few appearances. As the series progresses, we slowly learn more about them, until by the time Season 3 rolls around, the Shadows have become the series main antagonist, and the show's Myth Arc is in full swing.
• Battlestar Galactica (2003) draws most of its plots from conflicts between humans and Cylons, infighting within the fleet, and the overarching Myth Arc of finding a way to Earth. Along the way, however, seemingly minor details come up about the titular warship:
  • The miniseries establishes that she's old and about to be decommissioned.
  • Battle damage accumulates on the hull as the series goes on.
  • A third-season episode involves a malfunctioning airlock threatening lives, along with remarks on how Galactica would be in need of a major overhaul under normal conditions.
  • A similar remark about equipment malfunctions occurs the next season.
  • Finally, it is revealed that Galactica has started to fall apart from all the wear and tear over her many years in service, and the last few episodes of the series see many plots put on hold as the ship's critical condition begins to dominate the series.
• In the last half of season two of Blake's 7, Travis has been court-martialed by the Federation and is just as much a wanted man as Blake. Initially, he cooperates with Servalan covertly, but by the penultimate episode, he hints he's got a new agenda, which is fully revealed in the season finale and forces Blake to abandon the goal he's been attempting to achieve all season.
• While fans will debate endlessly about whether Joss Whedon was winging it or not, most Buffy the Vampire Slayer seasons are good examples.
  • Seasons 2, 3 and 4 show this pattern: a bunch of threats at the beginning of the season that end up being eclipsed by some bigger one.
    • Season 2 has the most rational explanation that there isn't really a singular Big Bad throughout the season until Angel goes evil, and once he does, everything else pales in comparison for the rest of the season... and maybe even for the rest of the series.
    • Season 2 also had to switch gears near the start because over the summer between seasons 1 and 2, the actor who played the Anointed One had grown too much to believably have him as the same unaging child vampire. The Anointed One was going to be the Big Bad of season 2.
  • The Big Bads of season 6 look like three fairly Harmless Villains, but there's also a subplot about Willow being addicted to magic, which is fairly minor at first. By the end of the season, one member of the trio has been flayed alive, and everybody is too busy trying to prevent Willow from destroying the world to care about the two others.
• Had it not been cancelled halfway through the first season, Crusade would have gone this way. The Drakh plague that dominated the storyline of the 13 filmed episodes would have been resolved by Season 2. The real Myth Arc, dealing with a conspiracy within EarthForce, would come to the forefront. As it was, we only got the barest hints, which weren't even obvious as hints until Word of God provided some perspective.
• Dexter: For the majority of the seventh season, the focus is on Hannah McKay and Isaak Sirko, both jostling for position as Dexter's main antagonist. Meanwhile, in the background, Maria LaGuerta investigates the accusations leveled at her late friend and former lover, James Doakes. Come the final episode, Isaak's dead, Hannah's in jail, and Maria's figured out who the REAL Bay Harbor Butcher is.
• In Doctor Who's third (revived) series, the entire plot of Utopia and the plight of humanity becomes negligible when a certain tenacious character makes a surprise return. Or so you think. In the next couple of episodes "The Sound of Drums" and "Last of the Time Lords", just when you've gotten used to the idea that the certain tenacious character is the big threat, it turns out that we aren't quite done with the far-future plight of humanity — and they aren't quite done with us...
• Season 7 of Homicide: Life on the Street, which is generally considered to be the worst season of the whole show, has a moment where Det. Sheppherd is beaten up by some suspects upon trying to make an arrest, had her gun stolen from her and her partner, Lewis, is nearly shot by them. What should have been a two- or three-episode plot ends up being a huge deal due to Lewis blaming her for nearly getting killed to the point of refusing to work with her for the rest of the season, he and the majority of the other characters (especially the women) believing her to be incompetent, and her having no way to prove herself otherwise. It isn't even until Bayliss calls Lewis out on his (usual) unforgiving nature that he starts to loosen up. Unfortunately, by then, it's the Series Finale.
• Kamen Rider Gaim:
  • The protagonists are originally concerned with the competition between local street dance crews, though they do notice some odd monster attacks on the rise. About a third of the way through the series, the "dance crew" storyline is officially retired as the show focuses more on the invading monsters, and it's eventually revealed that this is a Cosmic Horror Story with the power to reshape the world at stake.
  • This trope also applies to two of the secondary characters, Kaito and Mitsuzane. Kaito starts out as simply the head of a rival dance crew, who is a Social Darwinist but otherwise pales in comparison to the other threats out there, and even frequently allies with our hero Kouta when their goals align. But when those other threats are dealt with, he becomes the Final Boss since he, like Kouta, has been growing in power the whole time wants to use it to tear down and replace the world order. Similarly, Mitsuzane begins as Kouta's friend but gradually starts to hate Kouta, fall into madness, and make more extreme plans to shape the world to his whims. Subverted when, just before the final battle, his schemes finally catch up to him and blow up in his face, leaving him psychologically broken and a non-threat.
• Lost is naturally a big example of this. Just a small spoiler-free (not) hint: the Final Season (and the two that precede it) is not really about castaways trying to survive after the crash and to get off the Island anymore.
• This is how the Hand are built up in the Marvel Cinematic Universe Netflix shows. In the first season of Daredevil (2015), two of the Hand's members, Madame Gao (one of the founders) and Nobu (subordinate to Murakami), are members of Wilson Fisk's crime ring and are using Fisk to help them acquire property for Midland Circle. Even though they don't mention that they're part of the Hand, we know of the Hand's presence because of the ease that these two have at intimidating Fisk, while James Wesley is very uneasy being around Nobu. The first season of Iron Fist (2017) adds more depth to Madame Gao's role in the Hand and also introduces Bakuto, and both of these people indicate that there is someone else pulling their strings who wants to meet Danny but don't mention Alexandra by name. Finally, we are introduced to the remaining Fingers (Alexandra, Murakami, and Sowande) in The Defenders (2017).
• Kirsten Cohen of The O.C. drinks on-screen enough for Television Without Pity to have started a "Kirsten Cohen drink watch '03", but at the end of season 2, she immediately switches from frequent wine drinker to inst-alkie, complete with Wangst.
• In season 4 of Once Upon a Time, we have a minor subplot where Regina attempts to find out who wrote the magical storybook that says she is a villain under the belief that the author is responsible for her never finding permanent happiness despite being redeemed. The second arc of this season is all about a group of villains wanting to do the same thing and get their happy endings.
• The Kromaggs from Sliders grew from a semi-recurring menace into the series' Big Bad. It had little to do with the original premise and was poorly received.
• Star Trek: Deep Space Nine:
  • The Dominion, first introduced as a background plot reference in a comedic Ferengi episode, would go on to almost conquer the Klingons, the Romulans, and the Federation. They were also aided in season 7 by the Breen, a race that started as a bit of a throwaway joke.
  • Dukat. His final arc started as the E-plot, something to give comic relief while everyone else was fighting the Dominion. Then things escalated. And again. And ag— say, did he just figure out how to free the Pah-Wraiths? Which he considered gods in a previous episode? Oh shit...
• The second season of True Blood is mostly about Sookie helping Eric and the Dallas vampires find the missing sheriff, Godric. Meanwhile, there's a subplot going that has Tara moving in with a social worker who is secretly a maenad. For most of the season, the maenad, Maryann, isn't really much of a threat; she mostly just prances around holding sex parties and trolling Sam, committing a couple of murders while she's at it. However, after the Dallas plot is wrapped up, Maryann becomes the Big Bad and the main cast must team up to save the townspeople's souls from her control and stop her from killing Sam in a ritual sacrifice.

Music

• Played for Laughs in "Jack Sparrow" by The Lonely Island. The song was supposed to be a generic club rap with a hook by Michael Bolton. However, Bolton is so obsessed with the Pirates of the Caribbean films that he keeps interrupting the rap to sing about them instead. He switches it to Forrest Gump, Erin Brockovich and finally Scarface (1983) by the song's end. Apparently, he's a major cinephile.

Tabletop Games

• Frequently happens in Legend of the Five Rings due to the audience participation model used to determine the storylines. Actions taken by players very early on in an arc can come to dominate the storyline late in its lifetime.
  • The most memorable example is probably the first published story arc, The Clan War. It starts with the (at the time) six Great Clans coming into conflict with one another as they attempt to assume dominance while their emperor lies close to death, some of them consorting with the Empire's ancient enemy, the Shadowlands, in order to do so. The storyline concludes with the Shadowlands and its leader, Fu Leng, firmly established as the undisputed Big Bad of the setting, and the Great Clans forced to cease their war in order to wrest control of the empire back from Fu Leng and his undead hordes.
  • A more subtle example occurrs with the subsequent storyline, The Hidden Emperor, which contains several confusing, seemingly unrelated subplots with the abduction of Emperor Toturi I at its heart. At different points in the story, the Dragon Clan, the Kolat, and the resurgent Shadowlands all seem poised to emerge as the masterminds behind all the chaos. It's quite a surprise when the shapeshifting ninjas who had been a part of the setting since day one are revealed to be a Hive Mind under the command of an Eldritch Abomination who had instigated everything as part of their master plan to unmake all of reality.

Toys

• BIONICLE web serials tend to choose this route. More often than not, they set up a basic plot-setting, and either shove it aside or wrap it up within the first couple of chapters, to concentrate on something barely related. Sometimes, these plot threads connect, other times, they just sort of get forgotten.

Video Games

• BlazBlue introduces the Susano'o Unit in its first game, effectively a suit of magic armour operated by a human soul, with the potential to have Reality Warper abilities at full power. It gradually becomes clear that the "White Susano'o" Hakumen is, in fact, a Legacy Character, and that recurring villain Yuuki Terumi previously served as a "Black Susano'o" until he tore himself from the armour out of hatred for the duties that come with the role. This doesn't really matter compared to the advent of things like Izanami, Doomsday, and the Embryo — until the end of the final game. After all other villains have been taken care of, Terumi reveals himself as the disembodied spirit of the Destroyer Deity Takehaya Susano'o, who is free to reclaim his body now that the Restraining Bolt that prevented him from abandoning his job and destroying/conquering all reality is no longer intact.
• This is a common theme in the Fallout games: very rarely does the game's premise (finding a water chip for your vault, finding a GECK, locating your dad, finding the person who shot you, or locating your kidnapped son) actually match up with the game's finale (fighting the Master, fighting the Enclave, fighting the Enclave again, fighting the Legion and/or NCR, or fighting the Institute). Often, the starting plot is completely resolved before the end of the first or second act, and external circumstances prevent you from returning to your previous life.
• A subplot about Alchemiss' power increasing in Freedom Force vs. The Third Reich takes over the third act of the game, as Alchemiss goes insane and nearly destroys the universe.
• In Golden Sun: Dark Dawn, the first half of the game involves you trying to get a feather to fix your dad's flying machine so he can investigate the Psynergy Vortexes, all while you're being pestered by a couple of jackasses named Blados and Chalis. Then the two of them trigger the apocalypse, and you spend the second half trying to stop said apocalypse and bring them down. The Stinger shows a very large Psynergy Vortex outside your house, showing that it might not have been such a good idea to completely ignore that whole plotline.
• In the Marathon trilogy, an evil trapped inside the sun since forever is briefly mentioned once in a short piece of religious text of an alien planet in the second game, for the purpose of fleshing out a cultural Backstory for the game's real plot. Or so you think, until it turns out that the "religious texts" were actually accurate historical recordings, and the enemy's eventual attempt to destroy the sun (with a likewise briefly mentioned WMD) releases the chaos god. The entire third game revolves around putting it back.
• The evil organizations in all of the main series Pokémon games come into play as extremely minor obstacles in the way of the player's true quest (which is To Be a Master and Gotta Catch 'Em All), but swell in importance, numbers, and ferocity as the player progresses, and eventually eclipse the original quest in importance (at least for a little while). The fifth generation games, as some feel, was the first generation to avert this, by basically having the plot involving the evil organization introduced in the first town you visit and remain important throughout the entire game.
• Despite Sonic the Hedgehog (2006) being named after Sonic himself and being released as the main centerpiece of the franchise's 15th anniversary, Shadow and Silver's storylines have far more importance to the game's overall plot than Sonic's (which almost entirely consists of saving and losing the princess over and over again), to the point that by the "Final Episode", the events of his story are practically a mere footnote.
• In Ultima III, the Great Earth Serpent is just an obstacle guarding the entrance to the Big Bad's castle, which you need a password to get by. In Ultima VII Part II: Serpent Isle, you learn that the serpent in question was a cosmic force of balance, and removing it from its proper place threatens to destroy the entire universe as the serpents of Chaos and Order struggle unchecked.
• World of Warcraft:
  • The Old Gods started as a minor background aspect of the Scourge but have steadily escalated to become the driving force behind many of the game's events. With the Retcons of Chronicles they are now weapons of the Void Lords who are behind not only them but indirectly the Burning Legion.
  • In Warlords of Draenor the original goal of the players was to destroy the Iron Horde, with Gul'dan and the Burning Legion being part of a side plot. Due to the Iron Horde weakening quickly Gul'dan stepped in and seized control, making him and the Legion the true enemies of the expansion.
  • Battle for Azeroth was heavily advertised as being focused on the faction conflict. The appearance of Azshara in Kul Tiras and the overarching plot in Zandalar regarding G'huun, a pseudo-Old God, were technically sub-plots but players immediately suspected a rat. With the Rise of Azshara patch, the faction conflict was given a rather abrupt anti-climax to make way for the true enemy of the expansion, the Old God N'Zoth.

Webcomics

• College Roomies from Hell!!! initially focuses on three very different losers trying to live together while occasionally dealing with wacky supernatural baddies. At one point, Satan shows up, grabs a character's soul, and then is quickly dispatched. Satan is mentioned another couple of times but doesn't appear again for a while. Then it turns out that one of the characters is a pawn in his plan to destroy the world, and all the other characters join forces to stop him.
• Invoked and parodied in Darths & Droids, in which Anakin/Darth Vader is depicted as a minor NPC Spear Carrier (he isn't even given a name at first) who gradually grows more and more important as the DM is forced to integrate him into the story as a result of the players going Off the Rails yet again. Eventually, he jumps to being a Player Character, and from there, he becomes the Big Bad responsible for Order 66 and the fall of the Republic, thanks to Annie being The Roleplayer and taking his Lawful Evil alignment to its logical conclusion; since he's supposed to be the Token Evil Teammate, she plays him as being genuinely villainous to the point of betraying the rest of the party.
• This is basically how Misfile got its final arc started. For the most part, the majority of the story was about Ash and Emily dealing with their post-Misfile lives while growing up and discovering who they were while Rumisiel attempted to get back into Heaven to fix his mistake. In the background was a subplot going on in Heaven about angels being killed and chaos in the depository which came up every once in a while to remind you it was still there, but ultimately had little effect on the main character's lives. Then at the start of the final book, in the middle of the race that would have capped off Ash's high school life, an angel crashes down to all but tell everyone that the subplot needed to be dealt with right now, forcing the cast to basically drop everything and get to resolving the subplot and the titular misfile.
• Sluggy Freelance: Dr. Schlock's evasion of Hereti-Corp dates back to when he's forced to work for them, and even when HC becomes the main plot, Schlock is still a minor supporting character. His fugitive flight from them takes over more and more panels until "broken", when he takes over Hereti-Corp.

Western Animation

• In Avatar: The Last Airbender, you see a couple images of what looks like a turtle with a lion's head — there's a drawing of one in the Magical Library, a statue of one in the Earth King's palace, etc. Given all the other Mix-and-Match Critters in the show, you probably didn't even notice it. Well, in the Grand Finale, one suddenly shows up, reveals that it can talk, and gives Aang a Deus ex Machina so that he can De-power Ozai without killing him. One reason that this ending became so controversial is because of how out-of-nowhere this development felt.
• The Family Guy episode "Da Boom" features half-octopus Stewies multiplying out of control and eating most of the characters at the end.
• The Simpsons loves this trope; a good example is "A Tale of Two Springfields". It starts off being about a badger infesting a doghouse, but when Homer tries calling animal control, he gets distracted by the fact that the area codes have changed. The badger looks through a window growling menacingly, but Homer shrugs it off, saying there are more important things to deal with now. In the end, when all of Springfield is focused on the resolution of the episode's major plot, an army of badgers seize the opportunity to take the town by surprise.
• South Park: The first episode of Season 14's "Coon & Friends" trilogy is about Cartman trying to get Captain Hindsight to join his superhero team, with BP's recurring drilling accidents being the B-plot. Then BP unleashes Cthulhu and the last two episodes focus mostly on him, tying up Captain Hindsight's story in the second.
• We get a double whammy in Spider-Man: The Animated Series, first with the portal machine that a Monster of the Week builds, and second with the Carnage Symbiote, who is really only fought once or twice in the series. Not only is it used to kill Mary Jane, but the final battle of the show involves Carnage coming out of nowhere and trying to use the machine to destroy the entire multiverse. Word of God supposedly says that a reason why the show ended with an unresolved plot was that after saving all existence, they couldn't think of any more compelling plots for the webhead.

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