[[quoteright:237:[[Comicbook/{{Superman}} http://static.tvtropes.org/pmwiki/pub/images/SuperLoisAndLana.jpg]]]]
[[caption-width-right:237:[[CatFight Chick fight?]] [[GirlOnGirlIsHot That's so hot!]]]]

->''"It's like they had a parrot on the staff during the editorial meetings that just kept pitching "Lois gets super powers! Lois gets super powers!" over and over again...\\
\\
And they kept listening..."''
-->-- '''WebSite/SuperDickery'''

Being a SideKick, LoveInterest, or even just [[InnocentBystander general acquaintance]] to a {{Superhero}} sucks. There are [[IHaveYourWife kidnappings]], [[FriendlyTarget high mortality rates]], [[ShotgunWedding marriage threats]], SuperDickery and the ever present SidekickGlassCeiling to contend with.

If a setting isn't insecure about changing its [[StatusQuoIsGod status quo]], or wants to change the dynamic from solo hero, to duo, or even PowerTrio and [[CastCalculus beyond]], then the supporting cast may catch Contagious Powers and these side characters will [[SuperEmpowering permanently gain powers]], going up to SuperWeight class.

The opposite of the SidekickGlassCeiling and subversion of NeverBeAHero. When the {{Muggle}} supporting cast of a superpowered hero slowly [[HowToGiveACharacterSuperpowers gain superpowers]] over time. This is typically done when the series gets a little older and writers are tired of one of the characters always playing the DistressedDamsel in HostageForMcGuffin situations. The solution to stale plots like those is to simply give the cast members in question their own fighting powers so as to bring them in line with the rest of the cast, sidestepping questions about how [[WhatMeasureIsANonSuper "mundanes" are useless]].

----
!Examples:

[[foldercontrol]]

[[folder:Anime and Manga]]
* Happened in ''Manga/{{Bleach}}'' to several friends if [[TheHero Ichigo]], most notably Chad and Orihime. It was initially thought to be an effect of his massive power, but was eventually explained as an effect of [[MacGuffin Hougioku]] hidden inside Rukia during the first arc.
** Later chapters explained that [[spoiler: there is a field or cloud that increases spirit awareness/power and migrates across the world. It just so happened to be on Ichigo's hometown.]]
* ''MahouSenseiNegima'' does this a ''[[RunningGag lot]]''; any girl who keeps a close proximity to Negi will inevitably have either some sort of latent power, or gain a powerful artifact through a pactio.
* It's not superpowers ''per se'', but considering how ''Anime/DigimonTamers'' started off with only three characters having Digimon, it'd be quite jarring for someone to skip ahead to the final saga and see close to TEN tamers, as slowly, over the course of the series, every major character gets a Digimon partner.
[[/folder]]

[[folder:Comicbooks]]
* [[JustifiedTrope Justified]] example: anyone who becomes a GreenLantern, because all that it takes is [[UpgradeArtifact wearing the ring]]. Recent stories have revised this, explaining that it takes a certain kind of pure-hearted willpower to command the rings. The cynical GreenArrow tried using a ring and could only fire off a single arrow of light before getting drained.
** This is justified similarly with ''Comicbook/IronMan'' and his supporting cast. Since the series revolves around suits of PowerArmor, all it takes is Tony Stark lending the suit out for one reason or another, or simply designing a new suit for them to wear. Usually this happened when Stark was unavailable or he was trying to protect his SecretIdentity. Over the years, [[Comicbook/WarMachine Jim Rhodes]] and Pepper Potts have both worn Iron Man armor '''and''' had their own suits designed for them. Conversely, you have Obidiah Stane and his son who were business rivals that simply stole Stark's designs.
* ''{{Spider-Man}}''. Whoo. At first it's only Peter with superpowers. Then pretty much everyone he knows gets superpowers of their own. It varies if those powers turn them into allies or more villains.
** In vanilla Spider-Man, we've got Harry Osborn and Miles Warren who were introduced as {{Muggles}} but later became superpowered.
** This is played with in regards to Harry's father, NormanOsborn was introduced a few issues before it was revealed he was the Green Goblin all along. Spider-Man and the audience met the Green Goblin a few years before Norman Osborn hit the scene but Norman was introduced before it was revealed he was a super-powered villain. This decision supposedly led to SteveDitko leaving the series since he felt it was unrealistic.
** Mac Gargan was introduced as a private eye for one issue before turning into the Scorpion.
** ''Comicbook/UltimateSpiderMan'' is a bigger offender. In the beginning, Spidey is the only character in the main cast with superpowers. By the 100s, the Human Torch, Kitty Pryde, and Iceman are all hanging out at his school, Harry Osborne transformed into the Hobgoblin, Mary Jane got experimental goblin powers from an evil Spider-Man clone, and mutantphobic Liz Allen was revealed to be Ultimate Firestar, a mutant [=superhero=] CanonImmigrant. And after Gwen Stacy dies, she comes back to life as the Ultimate version of ''Carnage''.
** And then there's the recent ''ComicBook/SpiderIsland'' storyline, where ''all of New York City'' develops Spider-Man's powers, including long-time supporting cast members like Mary Jane Watson and J. Jonah Jameson.
* In ''SupremePower'', a mutagen spread by Hyperion's falling spaceship gave powers to nearly every other [=superhero=] in the setting. All of them were children at the time; the Amphibian was "infected" as she was being born. Later, the military's attempts to duplicate Hyperion's abilities using this mutagen also gave way to Tom Thumb and Redstone.
* [[WebSite/{{Superdickery}} Superdickery.com]] makes a running joke/drinking game out of this, telling viewers to "[[DrinkingGame take a shot]]" every time Jimmy Olsen from ''{{Superman}}'' is shown getting some kind of superpower.
* For most of the run of comic series ''{{Powers}}'' the two main detectives have both been muggles who investigated crimes associated with [=superheroes=] and [=supervillains=]. [[spoiler:Although one used to be a [=superhero=] until he lost his powers.]] Things get turned around, however, when [[spoiler:a contagious power acts as TheVirus, and one of them gets infected with it. Meanwhile, the [=ex-superhero=] is getting a new set of powers as well.]]
* This is what the parents of Tyler Marlocke in ''PS238'' hope will happen by putting their non-superpowered son in an environment absolutely dripping with superpowers. In a subversion, it hasn't worked (yet, at least), though he is learning quite a bit from the city's resident BadassNormal [[CrimefightingWithCash Crimefighter With Cash]], The Revenant.
** After travelling between dimensions and messing about with various parts of his surroundings , Cecil gained various EldritchAbomination traits. However, he only has these traits while in-between dimensions ( and possibly while in other dimensions). He retains [[spoiler: wings however ]].

* Happens a lot to the nearest and dearest of [[Comicbook/IncredibleHulk Bruce Banner]]. Even if one discounts those who gained their powers from the same gamma blast that created the Hulk, there is still Betty Ross - briefly turned into the Harpy, Doc Samson - who uses the Hulk's own gamma energy to gain super strength, his cousin Jennifer Walters - who becomes SheHulk due to a blood transfusion and Rick Jones - who time shared his body with Captain Marvel, was briefly a Hulk himself and is now A-bomb... a blue version of the Abomination... and [[spoiler: Thunderbolt Ross and Betty are Red Hulk and Red She-Hulk, respectively.]]
** Rick Jones wife Marlo is now the New Harpy, his old enemy Elliot "The Clown" Franklin is the Griffin, Brian Tablot (brother of Bruce's rival Glenn) is Grey, Gideon Wilson (the father of Bruce's friend Jim) is Mister Gideon... At this point it's as though everyone he knows somehow develops powers eventually, because you may find this to be his entire supporting cast plus interest.
*** An attempt at invoking this was rejected when Jim Wilson, Hulk's sidekick from TheSeventies, was dying of AIDS and asked the Hulk (at the time with Banner's brain) for a transfusion to keep him alive, like he had done for his cousin Jen. Hulk refused.
* Literally in ''Comicbook/{{Empowered}}''; three of the members of the "Super-Homeys" alone got their powers from ''post-human [=STDs=]'', and actually teamed up after meeting each other at a support group for it. One nameless [=superheroine=] contracted her powers from a cosmically enhanced cape, a guy who slept with a CuteRobotGirl found himself turned into a living robot himself, and one poor unlucky bastard named Protean (he used to go by the moniker "Glorpp") dissolved into a BlobMonster as a result of an [=STD=] he contracted from a GreenSkinnedSpaceBabe.
* The ''ComicBook/FantasticFour'' rarely have supporting characters who don't have one power or another. Johnny Storm's girlfriends either turn out to be [[SecretInvasion Skrulls]] or later become heralds of {{Galactus}}. Ben's girlfriend Sharon Ventura started out with powers but eventually turned into his DistaffCounterpart, becoming even more superhuman. They both dated Alicia Masters[[note]]Sort of. Johnny actually dated a Skrull spy named Lyja who was impersonating Alicia, then dated Lyja again as herself.[[/note]] who was mostly normal until her father, the Puppet Master used her for his own means. She also dated the ComicBook/SilverSurfer for a time and was briefly given cosmic powers. Then we come to Reed and Sue. Their kids have godlike powers, their nanny was a sorceress who trained the ScarletWitch, and Reed's dad was eventually revealed to be a time traveler. Even DoctorDoom is not exempt from this. His adopted heir Kristoff ended up in a suit of PowerArmor similar to Doom. Wyatt Wingfoot is a friend of the family and the only one without powers, it seems. Despite that, he is still a BadassNormal who has gone toe-to-toe with supervillains.
[[/folder]]

[[folder:Film]]
* Spider-Man has a knack for this, even in the ''Film/SpiderManTrilogy''. Both Osborns were introduced before gaining powers as the first and second Green Goblin, Peter met Otto Octavius a few times before he turned into Doctor Octopus, and he knew Eddie Brock before he turned into Venom. This is actually against canon since part of Venom's initial concept was that he was an unknown reporter who had a very personal vendetta against Peter. The idea being that Peter's heroics destroyed a life without him realizing it. The only villain Peter faced who he didn't know previously was the Sandman, [[spoiler: although he was Uncle Ben's killer]] so there was at least some personal connection to him.
** In ''Film/TheAmazingSpiderMan'', Peter plays a role in Dr. Conners' transformation into the Lizard.
* In ''Film/MySuperExGirlfriend'', a radioactive meteorite gave G-Girl her powers. When [[spoiler:Hannah]] touches the same meteorite, she gains the same powers as well.
[[/folder]]

[[folder:Literature]]
* In ''Reflex'', the sequel to Steven Gould's ''Literature/{{Jumper}}'', [[spoiler:Millie]] gains Davy's teleportation abilities by being teleported by him a large number of times.
* In ''Tik-Tok of Oz'', Dorothy finds out that Toto can talk, just like all the other animals in the Literature/LandOfOz.
* On the ''Literature/{{Discworld}}'', magic is very much like this. Leaked magic from Unseen University causes strange behavior in ants and cockroaches, makes a dog able to talk and understand at a human level (much to said dog's annoyance), and generates at least two tribes of sentient rats (one mentioned in ''Discworld/GuardsGuards'', the other in ''Discworld/TheAmazingMauriceAndHisEducatedRodents'').
* The pets of wizards in the ''YoungWizards'' series tend to "become strange", with the most common powers being increased intelligence and the ability to speak. Tom and Carl have a dog with super strength and a macaw that can look into the future, while Kit's dog Ponch develops the ability to create ''new universes''.
** After Kit uses magic to fix a remote control that doesn't work properly with its TV, the TV starts spontaneously developing new features, like receiving alien cable stations and hooking into alien chatrooms.
* In the ''{{Darkover}}'' novels by MarionZimmerBradley, the Ardais family's ''laran''- their hereditary psychic talent- is catalyst telepathy, the ability to awaken ''laran'' in others, often simply by living in close proximity to or interacting with their targets for long periods of time.
* In the ''WildCards'' books, powers are created by the Wild Card virus, which is not normally contagious. However, in one story, a character develops a form of the virus that can and does infect anyone he comes in contact with.
** Played with in that the virus is contagious, but the powers might not be. An ace passes along the virus genetically, but the kid still draws the same odds as every one else of dying, becoming a joker or becoming an ace.
[[/folder]]

[[folder:Live-Action TV]]
* ''Series/BuffyTheVampireSlayer.''
** Oz became a werewolf shortly after being introduced to the Scooby Gang.
** After four seasons of Willow's CharacterDevelopment--or, more to the point, of her [[TookALevelInBadass badass upgrades]]-- her magic makes her more powerful even than Buffy.
** In the last TV episode, Buffy and Willow [[spoiler:give hundreds of girls the same powers as Buffy, permanently.]] In the Season 8 comics, Buffy is still the main character, not because she's the most powerful, but because she's [[BigGood the leader of the good guys]].
* The beginning of ''Series/{{Heroes}}'' had several {{Muggle}} characters. Then they were slowly killed off, PutOnABus, or caught Contagious Powers of their own. By now the only major cast members without superpowers are [[strike:[[SuperStrength Mohinder]], [[SuperEmpowering An]][[KamehameHadoken do]], and]] Noah Bennett's family sans Claire. And really, it's probably only a matter of time for at least one of them as well.
** Some fans speculate that Mohinder's immunity to the Shanti Virus may qualify him for Hero status, though that's iffy considering he's only immune to one strain of the virus. Then again, blood type incompatibilities with his transfusion to Molly, The Haitian, and Niki haven't come up.
*** The lack of blood type incompatibilities could just mean he's Type O Rh negative, universal donor (as is the case of 2% of the population of India). Or just Type O in general (about 38% of the population of India) considering that 90% or so of the world's population is Rh positive and thus compatible. . .
* The first season of the 1990s ''Series/TheTomorrowPeople'' series, Megabyte is the only one of the characters without powers, but then (surprise!) he gets them in the last episode of the first season.
* ''Series/{{Smallville}}''. Thanks to their dominance in the GreenRocks market, the citizens of Smallville (often kids at Clark's school that he "[[RememberTheNewGuy knew]]") receive powers [[OncePerEpisode quite frequently]] in the early seasons, and of course Clark's supporting cast gets sucked in eventually.
** Lana gains precognitive visions for one episode. Several seasons later thanks to [[LightningCanDoAnything lightning]] she gets [[PowersAsPrograms Clark's]] [[strike:Flying]] [[{{Flying Brick}} Speeding Brick]] powers. Naturally, she loses them by the end of the episode but then later gets brick superpowers before leaving. Oh and she got vampire powers then gained heat vision by drinking Clark's blood some time in between.
** Chloe was briefly able to make people tell the truth, before the producers decided to give her a set of Healing Powers. Then her already [[HollywoodHacking improbable ability to hack anything]] was upgraded to superpowered proportions... which vanished when [[spoiler:Brainiac is removed from her body]]... and the healing power has seemingly been forgotten.
** Lex, it was hinted had an advanced immune system. He also received a set of fancy Kryptonian powers through an invisible power suit.
** Pete briefly gained Stretch powers for an episode thanks to [[ProductPlacement Stride Gum]].
-->'''Chloe''': [[LampshadeHanging Chewing gum? Is nothing sacred any more?]]
** Jonathan is also in brief possession of Kryptonian powers for an episode, although it's suggested the strain it put on his body significantly shortened his life expectancy. He also somehow healed Clark once although that may or may not be Jor-El working.
** Lionel was [[NewPowersAsThePlotDemands bestowed a number of Kryptonian powers as the plot demanded]] during his time as Jor-El's emissary.
** Oddly enough, Clark, who already had [[{{Flying Brick}} Speeding Brick]] powers and getting new ones each season, was gifted with [[Literature/TheDeadZone "Dead Zone" Visions]] for a single episode in the middle of Season 2 although it might be the artifacts rather than his innate ability. In [[DorkAge season 9]] he even gained two one-episode powers.
** And of course - Lana, Chloe and Lois ALL get superpowers when they're possessed by witches.
* In ''Series/LoisAndClark'', twice Superman's powers were transferred [[LightningCanDoAnything via lightning]]. One was permanent (until removed deliberately), and the other temporary. The villain of the week also attempts to copy the superpower-copying lightning in a lab enormously. She succeeds, turning a mouse into a superpowerful killer of cats. She briefly gains Kryptonian powers until beaten and the device used to reverse the effect. Strangely, this does not happen more.
** In one episode, Lois gets Clark's powers and spends the episode as Ultra Woman.
* ''Series/TheFortyFourHundred'' took this trope UpToEleven. It started with 4400 returned alien abductees, a few of which had superpowers. Then the government stops giving them superpower suppressant, and it turns out they ALL have superpowers. Then a scientist isolates the magical neurotransmitter behind it all, enabling him to synthesize a serum that can give ANYONE superpowers (though with a 50% risk of death). Then one guy, taking the serum, gains the power giving anyone around him superpowers (again, with a 50% risk of death for each person).
[[/folder]]

[[folder:Videogames]]
* At the start of ''Persona4'', only the protagonist has the power to enter the TV world at will and summon his Persona. Through the course of the game, everyone who joins the investigation team picks up both of these abilities.
* In ''Videogame/FinalFantasyXIII'', most of the population of Cocoon ''believes'' this to be the case with [[CursedWithAwesome Pulse l'Cie]] (that anyone who so much as looks at them funny becomes one, as well), though in reality, it takes [[DidYouJustPunchOutCthulhu slightly more effort]] to actually become one.
* [[JustifiedTrope Justified]] with KingdomHearts. First of all, Keyblades are the hinge around which many superpowers swing, and they're attracted to strength of heart and will. In the beginning, only Sora is able to wield a Keyblade, but his example of dogged heroism and huge-hearted compassion drives many other characters to push beyond their limits and gain their own: Riku, Kairi, and even [[spoiler:Axel]].
[[/folder]]

[[folder:Webcomics]]
* Clarissa spent the first few years of ''PointGuardian'' as a VoiceWithAnInternetConnection and provider of borderline superscience gadgets, mostly for main character Ultra. She recently acquired a copy of Ultra's powerset (prior to the EnergyBeing upgrade he got a few months later).
* ''WebComic/AxeCop'' cranks this UpToEleven, as superpowers are ''literally'' contagious in that they seems to be spread through bodily fluids and various other ways diseases are spread. One character developed dog-related superpowers after being bitten by a dog. It wasn't even a radioactive or genetically engineered dog.
[[/folder]]

[[folder:Web Original]]
* Not ''quite'' a purely accidental example, but: In the Literature/WhateleyUniverse, Generator picked up her roommate Tennyo's regeneration power in a mad science-powered attempt to get her seemingly permanent 11-year-old body 'unstuck' by using Tennyo as a template donor. Of course, there's also the bio-devisor student Jobe Wilkins who, if he put his mind to it, would be able to come up with quite a few ways to create ''literally'' contagious superpowers if his lab accident with the 'drow formula' originally meant for a prospective girlfriend is any indication...
** And then there's the way Residue got her powers.
[[/folder]]

[[folder:Western Animation]]
* The third season of ''StaticShock'' starts out with Richie getting super-intelligence powers and becoming the technologic [=superhero=] Gear. Virgil hypothesizes that Richie was exposed to the trace amounts of the mutagenic gas left on his clothes the night of the Big Bang, hence why Richie's powers took over two years to manifest. This makes it a ''literal'' case of contagious powers.
* ''WesternAnimation/{{Ben 10}}'': Season 3 Gwen starts training herself in magic, after refusing the call the previous season.
* In the 90s ''WesternAnimation/FantasticFour'' cartoon, Johnny was afraid this had occurred when he kissed this foxy redhead and she immediately burst into flame. Turned out she had some kind of mutant power she'd repressed due to accidentally burning her house down as a child.. Then played straight when she got extra powers from Galactus in order to become his herald.
* ''SpiderManTheAnimatedSeries'' introduced almost all superpowered heroes and villains without powers, having them gain them after they had some character development as Muggles. The result, it made it even more like [[DoomMagnet being around Peter Parker for about a week or so]] was enough to make you into a [=superhero=] or [=supervillain=].
** ''TheSpectacularSpiderMan'' does the same, introducing the pre-Goblin Osborns and pre-Lizard Dr. Connors, making pre-Venom Eddie Brock a ''regular,'' and introducing pre-Sandman and Rhino versions of Marko and O'Hirn as recurring petty thugs before being supervillain-ized. We also met John Jameson and Mark Allan before they became Colonel Jupiter and Molten Man, respectively. Black Cat appeared in-costume first, though.
[[/folder]]

----