...which may be a reference to Sailor Jupiter's debut in the Sailor Moon anime. She initially appeared to be just some random Huge Schoolgirl who held her own against one of the Quirky Miniboss Squad with just her bare hands. (To the viewers who ignored the clues. Her debut episode even mentioned Sailor Jupiter in the title)
Yuuna 'the Kid' in Mahou Sensei Negima! starts decimating robot invaders during the Mahora school festival to the utter astonishment of everyone around her. When the really really big stuff starts coming out, she does get outclassed though. Just like everyone except Negi, really.
With all that, she only got fourth place out of all the Mahorafest participants. Meaning there were three other bystanders even more badass than she was.
In the fourth chapter of Fullmetal Alchemist, Ed is fighting terrorists on a train in a hostage situation. When he makes it to the coal room, he quickly takes out one of the two terrorists, but the other manages to aim a gun at him... when the two stokers (the people who shovel coal into the train's furnace) suddenly come out of nowhere and start bashing the guy's head in with their shovels. It's to be expected from a World of Badass.
And in the 60ish chapter of Brotherhood, while Wrath is hanging from Greedlings leg, a nameless mook (with a Badass Mustache) manages to shoot him in the shoulder. This a man who was never even touched throughout the first 59 episodes out of 64.
Concurrently, there are some shots from a random Amestrian soldier's point of view, as he and his men rush up a staircase, and are swiftly shot with a machine gun in this enclosed space, and he goes behind a pillar while the others die or run. He just stays behind the pillar under heavy fire, and eventually kills the gunner and gets to the top despite being shot, and manages to shoot Greedling through the head, seeing him as a monster before falling over.
The real one comes when The heroes have been taken out by Father's Wave Motion Gun alchemy. He then is this close to absorbing Ed and Izumi to replenish his Philosopher Stone, when a random sniper bullet comes out of nowhere and nails Father right in the head! It doesn't kill him, but it does knock him down for a few seconds, saving Ed and Izumi,and setting up the good guys counterattacks and effectively leading to his defeat.
Henaro in The Tower of Druaga is just a random tavern patron who's forced to go along with the main characters when the military raids the building, and proves to be quite capable of standing up for herself. Ultimately subverted, as it turns out she was planted there to infiltrate the group.
Rurouni Kenshin: A sumo student left the academy after being bullied by a combination of The Bully and Jerk Jock. Rather than taking down the bully, Kenshin encouraged the bully's victim to stand up.
Frequently happens in the Digimon series. Usually, The Hero and The Lancer are the ones to gain the highest evolutionary levels, with the rest being one level lower. That doesn't, however mean that the others are helpless, and still are able to contribute to battles.
In Digimon Tamers, the Drunk Withpower mega-level Beelzemon has his gun point-blank at Gallantmon's head. The Champion-level Guardromon fires his attack at Beelzemon. It doesn't hurt him, but it does distract him long enough for Gallantmon to regain control of the fight and win.
In the JLA arc "Syndicate Rules," the Antimatter Universe Johnny Quick and his teammate Power Ring (disguised as the Flash and Green Lantern) are having their asses handed to them by Computron and the Rainbow Raiders. The civilians are thoroughly stunned to realize the two "Leaguers" are having a hard time with these D-List (at best) supercriminals, and immediately rush in and beat the crap out the Raiders with makeshift clubs, shovels, and two-fisted bystander action.
In What If?: House of M, every superhero and villain loses their powers. This leads to the Red Skull, with the combined forces of the Hand, A.I.M, and Hydra to try and take over New York, now that they have no competition. Iron Man tries to save the day, with the help of the other un-superheroes in new iron suits, but gets their asses handed to them. This leads Peter Parker, formerly known as Spider-Man, to jump into the fray with a Badass Speech and, with his old web shooter, smashes the cosmic cube the Red Skull is holding. The result: the ENTIRE CITY OF NEW YORK Zerg Rushes the Red Skull and his minions.
In the X-Men graphic novel God Loves Man Kills, main villain and Sinister Minister William Stryker is about to shoot Kitty Pryde after she gives him a "Reason You Suck" Speech on live TV. In the book's climax, Stryker aims his gun and the X-Men stand their ground. A shot is fired, but it's Stryker who falls over, as he was shot (non-lethally) by a police officer working security. The cop states rather obviously that Stryker was about to shoot an unarmed little girl, which is not the Word of God.
In one Thor story, tired after a destructive fight, Thor is sitting by an ambulance when a paramedic walks up to him and passes him Mjolnir, telling him that they found it in the wreckage. Thor only realises once the man walks away that he spoke to a rare mortal capable of lifting the hammer, and thus worthy of "the power of Thor".
A Diabolik story featured an insomniac guy who, upon seeing the title character (actually a very convincing impostor, but this insomniac man believed him the real deal), also known as King of Terror for, among other reason, his enormous body count and the fear he inspires, grabbed a precision rifle and gunned him down.
The Mighty Avengers tie-in to Infinity, sees Proxima Midnight, one of Thanos's generals, leading an army into New York City and demanding everyone's surrender. One old woman's response is to pick up a brick and chuck it at Proxima's head, shouting "No pasaran!" It touches off a mass response from the gathered crowd, and while "No pasaran!" doesn't have much effect, "Avengers Assemble" does.
In the first film, Spidey is about to be finished off by the Green Goblin when his bacon is saved by... a crowd of New Yorkers throwing bricks, pipes, etc at the bad guy.
Subverted in the second film when Spider-Man nearly kills himself stopping a tram from driving off the rails. After he's pulled back inside the tram by the passengers, Doctor Octopus shows up to finish him off, at which point everyone in the tram car stands up and proclaims that he'll have to get through them first. He casually knocks them all aside. At least they tried!
There's the black guy in From Dusk Till Dawn, a random guy who can punch a vampire's chest and pull out his still-beating heart on the first try. It turns out that this badass grandpa is Fred Williamson of 70s exploitation movie infamy. His war story about how he chopped up an enemy platoon with a bayonet (after getting his face blown off by a land mine) probably sheds a bit of light on how he could rip fat vampire's heart out, bare handed and throw vampire Tom Savini through an oak door. Meanwhile, the named characters still needed to use weapons to slay their vamps.
In Kung Fu Hustle, low-life crook Sing discovers too late that everyone in Pig Sty Ally could kick his ass all goddamn day. Then the shy, effeminate tailor turns out to be the most badass martial artist of the lot. Later on, Sing and his accomplice harass a salaryman on a trolley until he grabs both of them by the collar and starts pounding their heads into the seats.
In Shaolin Soccer the main character envisions a world where everyone uses kung fu in their day to day lives. In the end, we see a bunch of random people in the street performing amazing feats of Wire Fu.
Two blood suckers assault an ambulance in The Twins Effect that holds the heroine. Thinking the vampires are hurt, the driver stops and gets out to help them, not understanding what the heroine means by "undead". Despite his ignorance, the super humanly strong duo with the power of flight prove to be no match for the ambulance driver. At least not until they decide to attack together, then they manage a stalemate. The ambulance driver was played by the film's producer, Jackie Chan.
Vicki: (after being impaled on the skewer and right before getting her head crushed) "Go to hell!"
The priest from Brain Dead, who just ran into some zombies by complete accident: "I kick arse for the Lord!"
Diary of the Dead has the dynamite and scythe wielding, deaf, Amish zombie killer Samuel who introduces himself amidst blowing up the undead. Likewise the female paramedic who karate-kicks a standing zombie in the head.
The page pic is the nameless banker, played by William Fichtner, in The Dark Knight who takes on the Joker and his goons with a shotgun until he runs out of ammo. It turns out the bank is run by the mob. It's a good attempt, but the Joker still gets away. He only lives because the Joker preferred to scare the crap out of the guy rather than kill him, lodging a fake grenade in his mouth instead of a real one.
The bathroom brawl scene in Jesus Christ Vampire Hunter involves one of the vampires being killed by some random guy on the toilet. Using a plunger.
In X2: X-Men United, one of the random kids at the school turns out to be Syrin. When the spooks invade the school, she starts screaming and everyone in the entire building starts bleeding from the ears.
When a gang of Yakuza pull swords on Bae-dal in Fighter In The Wind, some guy in a hat (later revealed to be an old friend) leaps out of the crowd and fights them to a standstill - despite only having one hand.
In the So Bad, It's Good early 90s Cyber Punk film Nemesis, protagonist Alex Rain is fleeing some heavily-built, cyborg assassins on the streets of Shang Loo, "a low-tech Asian shithole". After he ducks around a corner, one of his pursuers runs into an old lady crossing the street and tries to muscle her out of the way. She mutters, "goddamned cyborg!", produces a large pistol from her handbag, and shoots the assassin three times in the back, then shoots him five times while he's on the ground.
The Avenging Disco Godfather has the title character (played by Rudy Ray Moore) yell to a random jogger while fighting drug pushers, "Howard, these men are angel dust dealers!" The jogger replies, "Okay, Godfather," and joins the fray. "Howard" was actually Rudy Ray Moore's martial arts instructor in real life.
In the Jim Jarmusch film, Ghost Dog: The Way of the Samurai, there's a short scene where the title character witnesses a mugger getting ready to attack an old man from behind. He seems to be considering intervening when the old man begins slowly putting down his groceries with almost arthritic movements... and then effortlessly floors the youth with a pair of martial arts kicks. Then the old man picks his groceries up again and merrily goes about his business, and out of the movie. We never see him again.
Gabby Johnson, the resident drunkard of Rock Ridge in Mel Brooks's Blazing Saddles, can take out bandits simply by grabbing them by the collar and breathing his "beer-breath" on them.
The scientists in the first chapter of the Commando Cody serial "Radar Men From the Moon" are surprisingly good fighters. They hold their own for a while against a pair of hired thugs as seen and commented on in this MST3K episode.
Most of Paris gets to be this in Disney's The Hunchback of Notre Dame, when in the climactic battle scene the crowd that had gathered to protest Esmeralda geting burned at the stake undergoes a mass Took a Level in Badass as a result of a Rousing Speech by Phoebus; they all join Phoebus in kicking the tar out of Judge Frollo's goon squad while Quasimodo is busy tending to Esmeralda (who is fighting for her life after having inhaled too much smoke). And we had actually seen hints of this earlier at the Festival of Fools, when Frollo orders his guards to arrest Esmeralda and the Street Performers in the plaza do their part to help her escape.
In Battle: Los Angeles, one of the civilians being evacuated by the Marines, Mr. Rincon, is doing his best to help the troops as they escape. During the freeway battle scene, he spots an alien flanking the Marines. Despite his lack of training, he grabs a fallen rifle and sprays the alien from the hip, taking it out, but taking a shot to the gut in the process. He eventually dies a few hours later.
At the end of Hitchcock's Strangers on a Train, a merry-go-round is careening wildly out of control, endangering the lives of dozens of people. The hero who volunteers to crawl under the rapidly spinning death trap, reach the mechanism at the center, and switch it off is... some random old guy who was never seen before and who is never mentioned again. We don't even find out if he survives.
In Baby: Secret of the Lost Legend, some random African tribesman in the climax guns down a half dozen of the villains.
In the Korean film The Host, when the monster first rampages through a public area, an American man takes it upon himself to mount a valiant attack on the monster before getting mauled. A news report later reveals that he's a soldier. This is probably done to compensate for the otherwise anti-American slant of the film.
The Avengers gives us an old man credited simply as "Old German" who would rather be Defiant to the End against Loki rather than Kneel Before Zod - it's made clear between his age and the dialogue that he was there the last time something like this happened in Germany, and he'll be damned if he sits by and lets it happen again.
In Captain America: The First Avenger a kid gets grabbed by a Nazi and used as a hostage. He's then chucked into the nearby river in order to distract Steve from pursuing the bad guy - and he's going to jump in after him when the kid yells up: "I can swim! Go after him!" A subtle form of bad-assery, but awesome nonetheless. Especially since not as many people knew how to swim at the time.
In the original Highlander film, a Crazy Survivalist Vietnam War veteran comes across the Kurgan decapitating another Immortal, and empties a clip from a submachinegun into him. The Kurgan recovers and impales him, but in an additional Bad Ass move, the vet survives.
TRON: Legacy: When Sam is cornered in the bar by four black guards, he's clearly outmatched, even with Quorra helping him. Bartik and several resistance members take on the guards, but are swiftly derrezed. As the fight plays out, bar patrons and resistance members get involved, one guard is derrezed by a patron stabbing him in the back, and two more are over powered and killed by other bystanders.
In The Living Daylights, The Brute raids an MI5 safehouse, slaughtering his way through numerous guards... and is held up by a single, nameless agent, who manages to not only hold off the man who gives James Bond trouble for several minutes, but also (probably) survives the attack.
At the end of The Hideous Sun Demon, an anonymous policeman tenaciously pursues the Sun Demon to the top of a gasometer, where they fight. Although the Sun Demon nearly kills the cop, he survives, resumes his pursuit, and ultimately succeeds in sending the monster toppling to his death on the street.
Subverted in Food of the Gods 2. During the giant rats' attack on the synchronized swimming competition, an audience member grabs a gun from a policeman and begins shooting, except that all he succeeds in doing is shooting other people. Lt. Weizel has to grab the weapon away from him before he can do any further damage.
In Unknown, Gina is a mere taxi driver and waitress, but she ends up killing three assassins (the first by sneaking up on him while he's strangling the hero and then injecting him with his own poison, the next two with Car Fu). The hero only kills one.
In the last Percy Jackson book, Percy's mom and stepdad are surprisingly badass when faced with a horde of monsters. This despite the fact that neither has any kind of supernatural fighting skills, and Percy's stepdad can't even see the monsters thanks to the Weirdness Censor.
A straighter example from the same series is Rachel Elizabeth Dare, who covers for Percy (who at the time was a perfect stranger) and puts the pursuing monsters on a false trail.
Invoked in The Wheel of Time, in which the world's most famous swordsman is said to have only been defeated by a random farmer with a staff. This is used as a lesson not to underestimate your opponents.
Meg Cabot's American Girl examines this from the point of view of the bystander. She just happens to be present at the scene of an attempted presidential assassination, and tackles the assassin, injuring herself in the process. She does nothing else heroic or extraordinary over the course of the book, and does not view herself as a hero, but the resultant fame changes her life in a variety of ways, good and bad.
Klaus Rosenthal and Francis De la Cruz from Rainbow Six (the novel, not the game). One's a seventy-something Holocaust survivor, the other a theme park employee and former Spanish soldier. Klaus, while being taken hostage, hides a paring knife up his sleeve, and when the Rainbow troops set up their ambush, he spot them lying in ambush (something the highly-trained terrorists failed to do, mostly because he was intimately familiar with his lawn). When the Rainbow troops pull the ambush, he stabs one of the terrorists with his knife, giving them a clean shot. Francis De la Cruz, meanwhile, is dressed up as a Roman centurion when the terrorists start taking hostages, and he goes after them with his sword. This is not a prop blade, either; this sword is made from genuine Toledo steel, and he cuts up one of the terrorists pretty well before another shoots him in the leg. (seriously, the last thing anyone expects while a terrorist plot is unfolding is for a freaking Roman centurion to flip out and start chopping the bad guys up) In both cases, the Rainbow troops, themselves just about the most badass people on the planet at the time, honestly consider both of their actions to be pretty badass.
In Executive Orders, Terrorists storm the day care where the presidents' pre-school aged daughter is being held. The only man there to pick up his kids that day is an armed FBI agent in plainclothes, who manages to kill both of them.
Robin Hood ran afoul of one of these men in the course of his adventures; when waylaying a beggar with a large bag because he was curious what was in the bag, Robin got pissed off by the beggar's insolence and nocked an arrow to threaten him. The beggar proceeded to take his staff and, in rapid succession, break Robin's bow, numb is sword arm, and knock him senseless before proceeding on his way. When Little John and George-A-Green attempt to avenge Robin's injury, the beggar pretends to surrender, offering them the money in his bag; Instead it turns out to be full of meal, which the beggar throws at their faces before beating the crap out of both of them. The nameless beggar, who never appears again, remains one of the few to soundly thrash the outlaws and walk away unscathed.
The Paladin of Shadows book A Deeper Blue has Will Carter, a former National Guardsman who helps Mike load his LMG and punches out a terrorist.
Played with to great effect in the original Whoops Apocalypse. A major sub-plot in the early episodes has the Soviets brutally interrogating a sweet, harmless elderly husband and wife whom they believe to be undercover agents for the West. The audience laughs merrily along at this, until suddenly...they beat the crap out of their interrogators, produce various spy-tech gadgets, and stage a jail break.
In Chuck, Big Mike ends up, on two separate occasions, completely owning enemy special agents that had been giving Team Chuck major problems earlier in the episode.
In Merlin an undead wraith crashes into Camelot and throws a gauntlet down before King Uther and Prince Arthur's feet. Though it is clearly intended for a member of the royal family, on two separate occasions a knight of Camelot grabs it before Arthur can in order to protect him.
In Jonathan Creek, a little old lady witnesses a group of men nailing another man into a coffin and attacks them with a tree branch and pepper spray. She takes down four men, and knocks at least two of them into an open grave before using her security whistle to call for the police. It's just a shame that she was actually interrupting a perfectly innocent magic trick...
In Desperate Housewives, a nameless extra is the one who ends up taking down and killing the insane gun wielding murderer holding a grocery store full of innocents hostage, after all evidence seemed to be implying that one of the main characters was going to.
Hikonin Sentai Akibaranger has a scene possibly inspired by the Bike Thrower example under Real Life below, with some differences - the bike belonged to Akagi Nobuo, who tried to help but couldn't, and the bike was hurled at the robber by the victim herself.
Simon does a medical version of this in Firefly. Disguised as a bystander in a hospital, he saves a random patient's life when the patient's normal doctor didn't do it right, and just keeps on walking.
In Season 4 of 24, Jack and Paul Raines take refuge in a gun store while being hunted by mercenaries. The two Arabic brothers who owned the store say they have lived here all their lives and refuse to abandon it, and help them repel the attackers.
In the Stargate SG-1 pilot episode "Children of the Gods", when the team breaks out of Apophis' prison along with a bunch of slaves, one of the random unnamed slaves kills a Jaffa with his bare hands and stands alongside the military personnel covering everybody else's escape through the Stargate to Earth.
Deconstructed in Flashpoint when every time an untrained bystander attempted to help the team or resolve the situation, it made things worse such as in "Grounded" where Parker would have been able to talk down the hostage takers if a passenger didn't try to be a hero.
GURPS Supers mentions these as one possible way of saving the heroes if the villain is getting the upper hand, pointing out that to avoid stealing the heroes' thunder it's better not to let the bystander beat the villain on their own, but rather contribute just enough to turn the tide.
By definition, EVERYONE in second-edition's version of Dark Sun that isn't a specific monster or named NPC falls into this category. To whit: in all other campaign settings, average NPCs had no level and anything done to them was "critical fail or total success." In Athas, a world where Everything Is Trying to Kill You is as literal as possible, the average person on the street is a level 3 Fighter. Later editions toned this down rules-wise, but it's still generally accepted that, with levels and such being a "relative" thing, everyone walking the blasted desert of a planet is functionally tougher than anyone from any other D&D world.
Older Than Steam: In King Lear, when Cornwall is brutally gauging out Glauchester's eye on stage, one of his servants challenges him to a sword fight, and actually delivers a wound that would eventually kill him. The only way he's beaten is to be stabbed by Regan when his back was turned.note In his essay "The World's Last Night", C. S. Lewis references this scene, and states that if "it were real life and not a play, that is the part it would be best to have acted."
In 1, Max can shoot a random SUV as it drives by the alley he's sneaking through. The car will crash and the driver will come at Max with guns blazing.
In 2, Payne gets attacked by assassins in his own apartment, and has to fight his way through the tenement building to safety. On his way, an elderly woman shotguns one of the assassins through her door and gives Payne her other rifle. Then Payne rescues a hobo from a burning corridor, and said hobo unpacks two pistols, claiming to be an ex-cop himself. Then Payne encounters a random prostitute who got locked in the lobby by the perps. But she also draws a gun of her own, and so both she and the hobo proceed to help Payne to take down all the assassins.
In 3, Max's neighbor will kill several of the mafiosos raiding Max's apartment complex.
In Dwarf Fortress, human and dwarven merchant caravans will keep visiting your fort even during a siege. And since they all have bodyguards proportional to the quantity of carried goods, they can often dispatch a whole sieging force by themselves, and then just start bartering with you as if nothing had happened.
In Adventure mode, if you're attacked and manage to make it back to a town, everyone will wake up, gather around you, and beat your assailant to a pulp.
In L.A. Noire, you come across shop owners once and a while who have actually managed to scare the shit out of their robbers beforehand. Also occasionally pulled by ordinary beat cops.
In one occasion, if you spend enough time chasing a perp, a random resident standing on his lawn will throw a decking punch and stop him for you.
The Wastelanders in Jak 3: Wastelander qualify, as not only will they shoot at you if you hit them, but when Spargus is overrun by Dark Makers, they fight back.
Blue in Red's quest in SaGa Frontier. When the Cool Ship gets attacked by pirates, Blue easily takes out the one who charges into his room. But because he's kind of a dick, he refuses to help Red because he doesn't like his name. In fairness, it differs only in language from his Evil Twin. His Good Twin, actually.
Fire Emblem Tellius: 3-13 Archer. While most of the time in Fire Emblem: Radiant Dawn the other army units are useless, one archer in this level is able to take on three laguz at once without dying. Best of all, he doesn't even have to do this. If he would simply remain at his starting position, the beasts would be unable to climb the ledge to attack him.
In Mafia II, if you rob a store there's a distinct possibility (which increases, the rougher the neighborhood) that some civilian will pull a gun and try to take you down. They just might, too, if you're not quick enough getting into cover or shooting them down.
In Super Mario Galaxy 2, there's a Gearmo who purposefully stands in the path of rolling Chomps and lets them collide right into him. The Chomps invariably explode apart on impact, but the Gearmo remains unscathed, despite enduring god knows how many Chomps.
In Dragon Age: Origins, Bodahn Feddic's adopted son Sandal is just an Idiot Savant with unusual skill at enchantment. Except at the endgame, he murders over a hundred Darkspawn, including several Ogres, by himself. In the sequel, he does it again, and then adds a pile of massacred demons on top of it. Precisely how this happens is not clear.
And mind-bogglingly in the second game, among Sandal's victims is an Ogre that was somehow frozen solid without any other enemy or thing in the area being similarly afflicted. Naturally Hawke can ask Sandal what happened to the Ogre, his response?
In the Fallout series, as well as Oblivion, random people will try to take you out if you try to do something evil close to them, and will pick up random weapons like assault rifles and submachine guns lying around nearby to do it with. Sometimes (especially in Oblivion) ties to Shoplift and Die.
The willingness of random people to take on the dragons in Skyrim has reached memetic levels among fans. It is quite distressing (or perhaps heartening) to note the number of people who will charge straight in a torrent of flame in order to beat a dragon to death with their bare hands. Though this might explain all the random people who tell you they think they might be the Dragonborn.
Sakupen, creator of the Dad Series, appears in the Dad Game as a random bystander in the middle of a panicked crowd in an early level. If you attack him enough times, he suddenly turns into the hardest boss in the game.
The giant pig at Link's home island in The Legend of Zelda: The Wind Waker. Pigs are Wind Waker's replacement for Cuccos in that they attack Link if he attacks them enough times, and the giant pig acts the same way, only he does more damage to Link in a single hit than any other enemy in the entire game.
In the school level of Lollipop Chainsaw, one student in the background actually fights back and defeats a few zombies before getting overwhelmed, unlike the others, who are mostly Too Dumb to Live.
Paper Mario has The Master and his students, residents of the game's dojo which are just as powerful as the game's bosses. The Master in particular can be optionally fought 3 times, with his final form being the game's superboss, even stronger than Bowser's final fight. Why he doesn't just take Bowser out himself or at least join the party to help is rather odd.
The opening of Paper Mario: Sticker Star shows several Toads grabbing Bowser by his tail and trying to pull him away from the Royal Stickers. Unlike the Master from above, these are just average Toad civilians without any special training or powers.
There is a cheat in some of the Grand Theft Auto games that causes every civilian to try to kill the player and another one that gives them weapons. Both cheats in tandem is a recipe for awesome.
GTA V features random citizens who pack heat by default, so the absence of police in an area doesn't necessarily mean the coast is clear.
As opposed to other such games, in Xenonauts some of the terrorized civilians are actually armed, which can lead to police officers killing space lizard commandos (though it's a rare sight).
Airman Higgs from Girl Genius is a low-level soldier who never distinguished himself, despite unreal stamina, enough strength to hold his own in a barfight with Jagermonsters, and a bit of a silver tongue.
In the third RP of Darwin's Soldiers, the heroes end up getting ambushed by Dragonstorm soldiers. They are assisted by some nearby loggers, who do remarkably well in battle against them.
Worm has Forrest, a civilian with no powers and a refugee in Brockton Bay who, upon seeing local supervillain Skitter fighting the serial killer Mannequin in order to protect the civilian survivors of Mannequin's teammate Shatterbird, steps in and hits him with a cinderblock to help take his head off. Mannequin having relocated all important organs to his torso, this doesn't kill him, but it does drive him off. Forrest goes on to become Skitter's second in command.
Later, during the Chrysalis arc, the students of Arcadia High do this, helping Skitter escape by mobbing the superheroes that were coming for her.
Subverted in the Justice League Unlimited finale. Wonder Woman, Shining Knight, Vigilante, and Sapphire are having a difficult time fighting an army of Parademons when one of the Chinese bystanders stops running, says goodbye to his wife, and runs to help. Wonder Woman tries to talk the old man out of it, until he one-hit K.O.s not one, not two, but THREE parademons, turns into a dragon, and whups several more, much to the heroes' surprise. The subversion comes in when the old man turns out to be J'onn J'onz, aka Martian Manhunter.
Played straight several times earlier in the series, though. The most memorable episode is "Patriot Act".
Earlier in the DC Animated Universe when Dan Turpin single-handedly turns the tide against Darkseid in Superman: The Animated Series. With Superman captured and publicly humiliated in order to cow humanity into hopelessness, Dan Turpin alone flips off the triumphant Darkseid and rallies the crowd behind him. Dan leads a counterattack, singlehandedly frees Superman, defeats several Parademons, and helps fend off the forces of Apokolips until the forces of New Genesis arrive to liberate the Earth. Now, while it's true that the viewers already knew Turpin was a tough cop, Darkseid had no clue who this guy was and thought he'd conquered the Earth by defeating its greatest champion. Unfortunately, this also counts as a Dying Moment of Awesome, as the fleeing Darkseid kills Turpin out of spite, prompting Superman to deliver the quote above at Turpin's funeral.
Played for laughs in an episode of The Simpsons when a hired assassin tries to kill Grampa with a machine gun. When Grampa runs to the retirement home's nurse and begs her for help, she initially reacts by trying to double his medication, but when the assassin bursts in and continues firing the nurse pulls a shotgun out of nowhere and repeatedly blasts him, yelling "OUR RESIDENTS! ARE TRYING! TO NAP!" with each exclamation point being a shotgun blast.
There is also the sleepover episode, where Mojo Jojo takes away the girls' powers and starts taunting them. The girls' normal friends soon become angered as he makes fun of them for being "normal girls" and proceed to beat him up. With pillows.
In Batman Beyond two-part episode "The Call", Inque caught a bystander to use as a hostage and Terry tried to talk her out of using innocent bystanders like that. In a similar subversion as the one presented at the finale of Justice League Unlimited, the bystander turned out to be a disguised Superman...unfortunately for Inque.
Scooby-Doo! Mystery Incorporated: Cassidy and the Gang hang out by the Clam Cabin and discuss the newest monsters, robots programmed to terminate her. When one of them climbs out of the water and attacks them, the shop owner, Skipper Shelton, sneaks up behind it, and shoots it with a harpoon gun, disabling it. After cursing at it, he offers the kids free food for the inconvenience.
In "Equestria Games", the pegasi from the stands who rushed in to help avert catastrophe via giant spiked ice-cloud, at least from the perspective of the ponies sitting next to them, unable to do anything. Imagine you're at a sporting event and something horrible happens on the field/track and the guy next to you immediately runs down to help while you feel comparatively useless, then multiply that feeling by the Olympics.
In "Twilight's Kingdom, Part 1", during the montage of Tirek and Discord steamrolling over Equestria, quite a few background ponies are shown bravely trying to fight back. Noteworthy is the first to fire off a magical blast at them, while a mob of pegasi (including the Wonderbolts and Derpy) try to swarm them.
A Delaware woman told USA Today that she had been walking home from church when her purse was snatched. A nearby man who had witnessed the attack jumped out of his car, chased the purse-snatcher through several backyards and over fences, and got the purse back. The man in question? Just happened to be her senator (and future Vice President of the United States) Joe Biden.
A Milwaukee man picked the wrong time and place to get into a "domestic dispute" when Mayor Tom Barrett was nearby.
Rukhsana Kausar, a farmer's daughter from India, living near the Pakistani border. After three armed militants invaded her home and began beating her father, she attacked the leader with an axe, disarmed him, and shot him dead with his own gun while his gang ran away in pants-wetting terror. The dead man turned out to be a high-profile wanted terrorist commander. Kauser was shortly therafter named Badass of the Week.
ElvisPresley was on the way to his hotel after arriving in Madison as part of a concert tour in June of 1977. He spotted two guys attacking a seventeen year old gas station attendant, and grumbled "Look at those two punks, I don't like this two-on-one deal." He got out of the limo, assumed a kickboxing pose and said "If you want a fight, let's fight." The three young men were so astounded they stopped immediately and began to ask for pictures and autographs instead. Before leaving he said "I found you as enemies; I leave you as friends."
Keep in mind that this was less than two months before Elvis died.
Mayor of London Boris Johnson encountered a woman being attacked while out riding his bicycle. He proceeded to take their pipe and chase them down the street calling them "Oiks"
Rob Van Dam chased down a mugger outside his comic shop, and Bam Bam Bigelow ran into a neighbor's burning apartment to save them.
The "Bike Thrower" in China. He stopped his bike in the middle of the road after seeing a lady being mugged by two assholes on a motorbike. Then as the robbers rode past him, he threw hisbike at them, knocking them down and leaving them for the cops. Then the hero just picked up his bike (trashed by the throwing) and walked away carrying it.
A retired Gurkha soldier was sitting quietly while forty bandits robbed the train he was in, until the bandits decided to try and rape the young girl next to him. Bad Move. He pulled out his service kukri and proceeded to kill 3 of them, and injured 8 more, until the rest ran for their lives.
Mixed martial arts Jon Jones chased down and apprehended a mugger in New York, then went on to win the UFC Light Heavyweight title that same night.
Adam West, one day, was chilling at the beach. He saw a man swearing at a topless girl and chasing after her with a knife. As West tells it, while he knew it probably wasn't going to help his reputation for mental stability, he still managed to take the attacker down, with a beach chair.
Richard Ramirez (AKA the serial killer known as The Night Stalker) was caught when he tried to steal a car. The car's owner, along with two neighbors and their sons, chased him down. As they ran, they recognized him from police photos that had been airing on the news and realized just who they were chasing. Once they caught him, they proceeded to beat the crap out of himin the street. When the police showed up, they did stop the men from outright killing him, but didn't bother to arrest any of them for the assault. Nobody was the least bit upset.
During Bill Clinton's term as President a man with a semi-automatic rifle shot at the White House. When the gun jammed, several bystanders tackled him to the ground. Including a man in a white cowboy hat.
Newark Mayor Cory Booker was on his way home one night when he saw that his neighbor's house was on fire and their daughter was trapped inside. He immediately ran into the flaming building and carried the girl out safely. People immediately started joking about the new standard for government service.
This follows a well publicized incident where he chased down a robbery suspect on foot while out for a jog and several instances where he went around the city getting people's cars unstuck after snow storms. May be disqualified from this trope since Mayor Booker seems physically incapable of actually standing by.
Some time in the 90s in Canberra, Australia, a man held up a public swimming pool with a shotgun. The manager refused to go along with the man's demands, and just when the man was about to shoot him, he pushed the gun downwards and took a shot in the leg. The assailant panicked and ran. The manager just happened to be an ex Special Forces Vietnam vet.
The 2013 Boston Marathon Bombings produced several of these, who can be seen on video of the event running towards the explosions, tearing down metal barricades with their bare hands and pulling people out, and several of them were credited with saving people who might have otherwise bled out by using makeshift tourniquets. One particular bystander named Carlos Luis Arredondo (who it turns out was already a badass in his own right) could be easily spotted wearing a distinctive cowboy hat in videos of the event and, in one particularly famous photograph (warning: graphic), running alongside and helping a man being wheeled away who had most of his leg blown off. He became an icon overnight.
Tank man, who to this day has his true identity unknown.
Most people wouldn't know that Steve Buscemi used to be a firefighter before he was an actor. He happened to be in New York during the 9/11 attacks, and the first thing he did was run all the way to his old fire station to volunteer for the rescue effort. It's quite likely he saved a number of lives that day.
In 1871, the James-Younger gang attempted to rob a bank in Northfield, Minnesota. Unfortunately for the gang, the town just happened to be chock full of these. The bank teller refused to open the safe, even when threatened with a knife and pistol whipped. When the rest of the town noticed something was going on at the local bank, they armed themselves and fought back against the famous outlaws when they attempted to escape. Between the shootout and the manhunt that followed, only Jesse and Frank James managed to get away. It is almost universally agreed upon that this was the event that lead to the downfall of the infamous outlaw and his gang.
Tameka Brown, who was riding a Philadelphia train when she noticed a man trying to attack a woman carrying a small infant. Brown stood up, put herself in front of the assailant, and successfully got the woman and child off the train to safety. But not before delivering the following Badass Boast to the attacker:
"I said Satan, the Lord God, rebuke you in the name of Jesus, you will not touch this woman."
A few schoolchildren were once mugged on a public train in Munich, Bavaria by two teenage junkies, who wanted to take their money. A middle-aged businessman, Dominik Brunner, intervened and escorted the kids off the train at the next stop. When the teens decided to go after them, he tried to hold them off with his bare hands. They beat him to death.