Bit Part Badguys

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 a Mook. 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 Temporary Love Interest 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.

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 Versus Seriousness. 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.

Common varieties include Bank Robbers, Thuggish Bar Patrons, Muggers, and generally Stupid Crooks. Also known as the Lowly Criminal.

Sub Trope of Bit Character; Super Trope of Mugging the Monster. Will often be given Kick the Dog or Politically-Incorrect Villain traits, if only to justify their getting a comeuppance. 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 the climax.

See Random Encounters for the Video and Tabletop Games version of this trope.

Anime & Manga

 * 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 of Berserk basically existed for Guts to show off his repeating crossbow skills and his gigantic sword for the first time.

Comic Books

 * 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.
 * The beginning of Sin City's 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.

Film

 * All over the place in all three of the Spider Man movies.
 * Dirty Harry: Some bank robbers.
 * 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 Darkhorse 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 and 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 the third film being a bit more of a tonal inversion of the biker bar scene from Judgment Day.

Live Action TV

 * As Buffy the Vampire Slayer continued, vampires gradually lost their Villain Pedigree, going from Big Bads to Monsters of the Week, to Mooks, until in the later seasons 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 then 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 from Torchwood 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 The Not Secret and Jack's return.
 * Poor old Cenred from Merlin. 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 happened 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.

Video Games

 * The Powder Gangers in Fallout New Vegas are a gang of escaped convicts. They're probably the weakest faction in the game and play no role in the main storyline.
 * The general formula in the Touhou Project 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.

Webcomics

 * In Sluggy Freelance Oasis takes down some random convenience store robbers, establishing her as a Vigilante Woman for the "Phoenix Rising" Story Arc.

Western Animation

 * 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 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.
 * 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 had a ton of these, especially in earlier seasons.