They're not the Big Bad; they're too small time for that. Heck, they're not even Monster of the Week level. But they're not working for another villain, either, so they're not really Mooks. These are Villains whose duty is to show up for a single scene, maybe two if they're lucky, and cause some minor trouble before the heroes kick them into next week and move on to the real plot.
Why bother including such a meaningless bad guy? It could be the story was running a little light on its action quotient and needed an excuse for some mindless violence. Maybe the writers wanted to show what the heroes' lives are like in-between more significant adversaries, or create an Establishing Character Moment for a hero we don't know very well yet. Maybe the episode was running a little short, and they had to fill up an extra five minutes with something.
Or maybe, while the Bit Part Bad Guys themselves aren't important, something that happens during the fight with them is. The hero might meet the Girl of the Week by saving them from one of these villains, or maybe it's during one of these quick fights that the Superhero will discover something's wrong with their powers, or maybe, because the hero was busy taking this bad guy down, they weren't at home to stop someone from getting kidnapped or worse, which may even elevate them to the level of Small Role, Big Impact.
Whatever the case may be, the Bit Part Bad Guy always gets the short end of the butt-kicking stick. They'll almost always be quite low on the Sliding Scale of Villain Threat and, compared to the rest of the story, on the silly side of the Sliding Scale of Silliness vs. Seriousness. Now it must be said that all this doesn't mean that they are necessarily ineffectual or not a threat to a random citizen, it just means that they are small fries in a much bigger pond. They can be quite dangerous and evil on their own for non-powerful heroes and will often in fact be given Kick the Dog or Politically Incorrect Villain traits, if only to justify their getting a comeuppance. The best hope a Bit Part Bad Guy has is to make a strong enough impression during their brief appearance that audiences demand they be brought back again, possibly upgraded to Monster of the Week status. Only once in a scarlet moon can such a villain even dream of becoming Big Bad material, though. Their tendency to think small and opportunistically look for easy targets generally disqualifies them from becoming someone with grander plans or vision of any sort.
Sub-Trope of Bit Character and Plot-Irrelevant Villain; Super-Trope of Mugging the Monster. Common in a Batman Cold Open, when said Cold Open doesn't feature a recurring villain; however, Bit Part Bad Guys can show up anywhere in the story, up to and including right before (and after) the climax.
- Darker Than Black has occasional appearances of Yakuza, Triads and Tongs and sundry thugs, most of whom exist just to be beaten up or killed in horrible ways by major characters.
- The Snake Baron's bandits in the first story arc basically exist for Guts to show off his repeating crossbow skills and his gigantic sword for the first time.
- The Female Apostle from the very first scene in the manga also acts as this, showing how ruthless Guts can be (though it's later revealed that she was the one who ate Corkus during the Eclipse).
- And one that escalates from minor antagonist to a (not-so) supporting member of the cast is Corkus, whose attempt to assault Guts leads into his integration in his very own Band of the Hawk and is not followed by anything else other than verbal assaults given his self-consciousness about his chances against him.
- Muteki Kanban Musume, being a deconstruction of the Fighting Series Played for Laughs, presents protagonist Miki as she encounters an unfortunate thief, minor Yakuza, and Japanese Delinquents, all of them only there to Mug the Monster and give her an excuse to curbstomp them, and then be forgotten.
Delinquent: Hey Missy, are you going to pretend that you didn't bump into me? You shouldn't distress us ordinary citizens. Maybe you should pay me as an apology.
- Codename: Sailor V has a few ordinary bandits and other criminals who exist only to show that Minako wants to humiliate the police by stealing their job, introduce a number of police officers as recurring characters and explain why Sailor V is a celebrity by the time of Sailor Moon. The plot of one chapter was kicked off by Sailor V wasting time in beating up two bullies, thus not having time to change back into Minako to take part to a lottery and winning a vacation to Hawaii as Sailor V.
- Richard Hellsing, the unnamed vampiric priest, Leif and Jessica from the beginning of Hellsing. The prostitute from the anime as well.
- In Dragon Ball, Goku visits West City looking for Bulma and, after earning 100,000 zeni in a street fight, is accosted by some criminals thinking he's an incredibly easy mark. Little do they know that Goku is Nigh Invulnerable and trained with the world-famous Turtle Hermit, and after he headbutts one into a wall his buddy suggests he asks a policeman.
- Marvel Comics have loads of these villains who show up in single issues or possibly in the middle of larger story arcs just to get beaten up: The Rhino, The Wrecking Crew, and The Blob just to name a few. That's not even getting into the numerous nameless crooks that crime-fighting superheroes beat up on a regular basis, who are lucky enough if they even get a line in.
- Sin City:
- The beginning of A Dame To Kill For features the private investigator main character spying on an abusive boyfriend and beating him up when he tries to hurt his mistress.
- Also in ADTKF is a brief scene where Marv shows up to take out some bad guys at Kadie's. This is subverted in that Marv was a secondary character in that story.
- Hell And Back also features a brief scene when Manute shows up to fight Wallace. Manute was working for a different mob boss that had ties to the Big Bad but otherwise, this was a bit part for him.
- Generally any of the petty criminals Judge Dredd deals with on a daily basis are this, particularly in one shot strips. Even in some of the Mega Epics, Dredd can be seen cracking skulls or getting into firefights with minor criminals while musing over the greater storyline.
- In a Batgirl (Rebirth) Annual, eco-terrorist villain Red Spur shows up in the two first pages and is chased away by Batgirl and Supergirl before the beginning of the main plot.
- In Many Happy Returns, super-villain Rebel harasses Supergirl several times until the Girl of Steel gets tired of beating him up and scares him away stating he was not important. He was something to do until the real Big Bad came along.
- In Gankona, Unnachgiebig, Unità, the rude chef, the homophobe, and the bully were all minor villains of sorts. Although not given names, they do play a part in the plot.
- The Vow has a group of bandits who kidnap Lady Lianne in hopes of a high ransom. In addition to her being rescued by Lord Shen providing action and relationship development, the sadistic way Shen personally executes the bandit leader Haun serves as one of the warning signs of what he becomes in the future. Most of the other bandits die as well, and the rest aren't heard of again.
- A Bug's Life has an example in the smallest way possible both figuratively and literally with the Fly Brothers who do not even meet/interact with Flik at all. They only try to cause a bar-brawl in order to get back at Francis because of some earlier cutting remarks which instead ends with everything in the bar turning topsy-turvy including a huge misunderstanding that leads to Flik mistaking the Circus Bugs for warriors and hiring them.
- The very first monster that Hercules encounters after completing his hero training, is the River Guardian Nessus who is in the process of forcing Meg upon him. Naturally, he comes between them saving her and costing Hades a possible recruit (and leaving the river unguarded), essentially also coming between a bit-part bad guy and his chance to escalate into a Mook (not that this would give him much more importance seeing as how Herc dealt with most others of course).
- Ice Age: The reason that the two brontotheres Carl and Frank want to murder Sid is because he, in his characteristic clumsiness ruined a rare delicacy for them. There isn't much of an interesting plot let alone a film that can be made with such a motivation, so they fight Manny, Manny saves him, Sid latches on to him for protection and they (mostly) depart from the story.
- In The Incredibles, Bomb Voyage's confrontation with Mr. Incredible is significant only in that it gives Buddy an opening to try to get recruited as a sidekick and puts the hero under enough pressure to sharpen the rudeness of his rejection.
- All over the place in all three of the Spider-Man Trilogy movies.
- The bank robbers from Dirty Harry were basically there so Harry could show off his skills with the .44 Magnum and deliver his famous "Do you feel lucky?" speech.
- Two muggers show up at the beginning of the first Tim Burton Batman movie, robbing an innocent tourist family (with one mugger pulling a Kick the Dog moment by turning his gun on the family's kid), laying down the fearsome reputation of "the bat" and then getting their asses kicked by the Batman.
- Just about every Batman film since then has featured at least one such character. Batman Returns included a brief scene with a nameless, nondescript mugger (and, it is strongly implied, rapist) who exists only as an Asshole Victim to get butchered by Catwoman — and, of course, to establish that Selina Kyle has Taken a Level in Badass after all the injustices done to her and will never be the same again.
- Batman Forever, on the other hand, featured an entire street gang sporting a weird combination of tribal face paint and Tron-like glow-in-the-dark uniforms who are so eye-catching that they veer dangerously close to Ensemble Dark Horse territory. What makes this so jarring is that they only appear in one scene, and then only as an opportunity for Dick Grayson (the future Robin) to demonstrate his latent fighting skills and also to work through his great anger at having seen his entire family murdered by the Dragon of the film, Two-Face. (Interestingly enough, a lot of planning went into the creation of these one-shot villains, with the film's costume designers studying Aboriginal rock paintings to get a feel for how they should look.)
- Batman & Robin, by virtue of its notoriously Biblical cast of characters, has two instances: the punk bikers whom Dick Grayson and Barbara Wilson race on motorcycles through a tunnel in the "bad" part of town; and another group of Day-Glo, tribal thugs who exist only for Bane to have somebody to beat up.
- In the Line of Fire begins with Clint Eastwood's character busting unimportant counterfeiters while undercover.
- Steven Seagal's Out for Justice features some random goons in a bar ripe for beating up.
- The 1978 Superman movie has a mugger go after Lois Lane... with Clark Kent right next to her.
- In Superman Returns, Superman's first act upon returning is against a pack of bank robbers, armed for bear.
- The two muggers that try to rob the blinded Jenny soon after the first shootout of The Killer, only to get beaten up by Ah Jong.
- The first humans the T-800 interacts with in the first two Terminator movies, with the parallel scene in Terminator 3: Rise of the Machines being a bit more of a tonal inversion of the biker bar scene from Terminator 2: Judgment Day.
- Teenage Mutant Ninja Turtles has two scenes involving purse snatchers.
- The first, which serves as the Turtles' introduction, has April getting mugged by a bunch of bad guys who wanted her purse. One of Raph's sai is lost during the battle, and is only reclaimed when April is attacked by the Foot Clan sent by Shredder to silence her.
- Another scene involves Raph getting a purse back from two more purse snatchers and then scaring them off. The two then encounter vigilante Casey Jones, who is a lot more vicious in dealing with them, setting up a fight between him and Raph, who doesn't share his methods.
- Block and Tackle of the H.I.V.E. Series have little impact on the story besides what others tell them to do. They are simply generic mooks who happen to be mean, and show up to terrorize the protagonists in every volume whether or not they contribute to the plot. They're usually gone in five pages or less.
- Duke, a villain from the Warrior Cats book The Lost Warrior is one of these. His only reason for existing was so that Graystripe could fight someone in the first book, and out of all the villains in the series, he is one of the quickest to go down.
- Buffy the Vampire Slayer: As the show continued, vampires gradually lost their Villain Pedigree, going from Big Bads to Monsters of the Week, to Mooks, until in the later seasons (around Season 3 or so) they appeared almost exclusively as Bit-Part Bad Guys. We'd see Buffy patrolling the graveyard, quickly dispatching a few vampires who don't even get a single line, then we'd shift scenes to the real plot of the episode. Other kinds of demons would occasionally fill this role, too, but since those required more expensive makeup effects than vampires, they tended to be saved for more important roles. To the point where it was lampshaded in song.
- While occasionally having one or two episodes devoted to them, the Weevils fall under this. If any character needs to be in a specific place at some point during the episode in order for the plot to work, more often than not they'll be hunting a Weevil. They're so minor, "weevil hunting" is the excuse Jack and Ianto use when they need to sneak out of work for some alone time.
- The Blowfish in "Kiss Kiss, Bang Bang" is basically used to set up Torchwood Three's status as Everyone Knew Already and Jack's return.
- Poor old Cenred. He was only incorporated because the Big Bads Morgana and Morgause needed his army to overrun Camelot, and he never gets to fight either Arthur or Uther before he's killed off in a classic case of You Have Outlived Your Usefulness.
- It happens again with Helios in series three, a warlord whose sole purpose is to provide the man-power for a takeover, and then die in battle.
- The subjects of the Batman Cold Open in Person of Interest.
- Across the Marvel Netflix shows, Turk Barrett tends to function as one. While he starts Daredevil (2015) season 1 as an indirect associate of Wilson Fisk's, by season 2, he's an independent smalltime Arms Dealer who sells guns that don't work. Then in Luke Cage (2016), he's easily fleeced out of money he was promised by Tone for ratting out Chico because of Cottonmouth killing Tone (and in season 2 there, gets his pot shop vandalized by Luke and Danny). In The Punisher (2017), he also has the unlucky fortune of giving Frank a pink Ruger Mini-14 rifle.
- Invoked by Ash regarding Ed, in Evil Dead: The Musical. Then doubly subverted, because Ed gets a song - "Bit-Part Demon" - before he gets shot, likely because not being a Bit Part Bad Guy meant he really was a potential threat. This is lampshaded by Ash immediately afterward.
Ash: Now you'll have a bit part... in hell!
- Ace Attorney games often include one of these as the culprit for the first trial that serves as a tutorial for new players.
- Fallout: New Vegas:
- The Powder Gangers are a gang of escaped convicts. They're probably the weakest faction in the game and play no role in the main story line, beyond being warm up for players at the beginning.
- Other than possibly The Fiends and White Legs-who both have a loose alliance with The Legion and are genuine threat to the region-pretty much any group of raiders in the games are this.
- The general formula in the Touhou series is that the first two bosses will have absolutely nothing to do with the plot, and the third will actually kick the main plot off (either by being loyal to the villains or leading you to them). These bit part bosses are often quite popular (one eventually starred her own game!) and most of them are grouped together in fanworks. Exceptions to both rules exist though.
- Urbzville in The Urbz is terrorized by 3 villains, Urangoo McBain, Kiki Blunt and Harry Snivel, who show up once in a while to mug the local Urb and generally cause trouble. However, once the player perform the district's Power Social move on them, they'll leave for good.
- Fire Emblem games almost always have the opening chapter deal with the protagonists army facing bandits or pirates raiding villages. Gazzak and Batta are particularly memorable examples. Occasionally criminals will show up after the early chapters as filler baddies outside of the main conflict.
- In Sluggy Freelance Oasis takes down some random convenience store robbers, establishing her as a Vigilante Woman for the "Phoenix Rising" Story Arc.
- Arguably Daimyo Kubota from The Order of the Stick. While it's noteworthy that Kubota is a competent villain and hangs around in the comics or a fairly decent stretch of time, in the end he's just a scheming noble whose ambition is to take over his particular Deadly Decadent Court, largely by political manipulation and taking advantage of the local justice system. By comparison the comic's Big Bad is a sadistic and cruel Person of Mass Destruction who killed an entire room of paladins with a bouncing ball, is looking to Take Over the World, and stands a pretty decent chance of actually destroying the world along the way. Kubota is pretty small time in comparison, regardless of the amount of attention he got in a minor story arc. Lampshaded when V casually murders Kubota and then asks in exasperation "Now can we PLEASE resume saving the world?"
- In El Goonish Shive, the mugger that threatens Sarah and Grace in the dark alley serves only to let Grace reveal her half-squirrel form and telekinesis.
- Generator Rex often begins its episodes with Rex beating the tar out of a rampaging EVO and usually curing it afterward.
- Justice League did this occasionally, in one case with Batman and Superman fighting some sports-themed villains while casually talking about Captain Marvel. Apparently they're so caught up in the conversation they forget what the bad guys were even after in the first place.
- The Box Ghost from Danny Phantom. Until he gets his hands on ''Pandora's Box'.
- The general census amongst Static Shock fans was that, should Carmendillo make appearance, he usually fills this role.
- Teen Titans had a lot of these, usually of the bizarre monster variety.
- However, Control Freak made a good enough impression during his brief fight in "Fear Itself" that he was later made the main villain of a couple episodes.
- Also Dr. Light was used as the punching bag to show Raven losing control of her emotions briefly. Which leads to a funny Call-Back when Dr. Light shows up again:
Raven: Remember me?
Dr. Light: I'd like to go to prison now.
- Batman: The Brave and the Bold had a lot of these, mostly in the Cold Opens, but many times as a way to start or end the story proper.
- Codename: Kids Next Door has a ton of these, especially in earlier seasons. Ultimately, Count Spankulot is the only one to graduate to full-on Monster of the Week.
- Amazing Rope Guy from WordGirl, whose incompetence is to the point that when criminals go on the rampage after she is weakened by a Kryptonite equivalent, he's the only one she catches.
- SWAT Kats has a couple in its extensive Rogues Gallery.
- In "The Giant Bacteria", Morbulus seems to be the episode's main villain, complete with a unique gimmick (360 degree vision, due to literally having eyes in the back of his head as well as the front). Then he runs into Dr. Viper. It doesn't end well for him.
- Chopshop shows up for the first half of one episode ("SWAT Kats Unplugged") and is never seen or mentioned again. The main reason he's remembered is because fans still debate whether T-Bone meant it literally when he called him a "laughing hyena".