Innocent Bystander

Not much a wealthy Socialite and her chauffeur can do here but keep their distance.

Ah, the Innocent Bystander, where would Villains be without them to use as Human Shields and the heroes to rescue in a Hostage for McGuffin? This noble profession has been much maligned by its incredibly high mortality rates and penchant for being in the wrong place at the wrong time.

Though similar to Muggles, the main difference is that the Innocent Bystander is not necessarily clueless or mundane (superheroes, wizards, or mutants can be innocent bystanders in the right, or wrong, circumstances), they just happen to be near a situation most qualified heroes would be hard pressed to escape alive. Essentially, they are those who must be protected, rescued or saved from a villain who will eat, kidnap, torture, or kill them. Since they're pretty expendable, it's even odds a few will be killed just to show how evil the bad guy is.

If the Bystander gets dragged along for the ride (be it as a hostage or a press-ganged helper for the hero), they may get upgraded to Mauve Shirt. If a Running Gag is made of how the same Bystander(s) keep running into the heroes, it's an example of a Yuppie Couple. If there's a whole bus full of these, it's a Bus Full of Innocents.

Quite a few series start with this premise. Arthur Dent of The Hitchhiker's Guide to the Galaxy is essentially an Innocent Bystander caught up in events he can't understand. By the end of the series he becomes something of a Heroic Bystander, though. They do get a chance at the spotlight sometimes though; check out Innocent Bystander Series, and its cousin trope the Lower Deck Episode.

Innocent Bystanders are often the targets of:

Compare with the Action Survivor (who is essentially an Innocent Bystander as an action movie protagonist).

Contrast Badass Bystander, Invulnerable Civilians.

Examples of Innocent Bystander include:

Anime and Manga

Okajima Rokuro in Black Lagoon—who just so happens to be the main character.
Brutally subverted in the first episode of Elfen Lied where The Ditz secretary Kisaragi, is beheaded and used as a body shield by the main character Lucy, possibly showing how ruthless and sadistic she is.
- Then again, it's Lucy we're talking about. The same Lucy who ruthlessly murders whole families simply because she needs a place to sleep. Even if you can get her doing it to the cruel orphanage kids as she both gets broken and finally gains access to her powers, the Kisaragi deal and the families are... not as justified/understandable/whatever. Even more so when this also includes Kouta's father and sister.
Akumetsu, no matter how extreme his plans get, will never let the innocent become involved. It's part of what keeps him from Jumping Off the Slippery Slope.
Rushuna's first run-in with the Jester in Grenadier is a straight example, with the Jester even doing a bit of Lampshade Hanging as he notes that while Rushuna can dodge the blasts of his gun, her less-than-super friend sure as hell can't.
These sorts of characters are often used in Chrono Crusade to show just how dire the situation has gotten—or how badly the heroes have screwed up. Near the beginning of the series, innocent bystanders are caught in the rubble after a fight Chrono and Rosette have with demons—luckily, Azmaria has healing powers. Later in volume 5 of the manga, several civilians are caught in a battle between Aion, Viede, and Chrono in the middle of an Unstoppable Rage. Many of them are killed because of CHRONO'S actions, and not the bad guys as much.
Winry's parents in Fullmetal Alchemist. Winry nearly becomes one of these herself when she overhears that Scar killed them.
Poor, poor Rangyaku and Keikei in The Twelve Kingdoms.
Saji Crossroads and Louise Halevy from Mobile Suit Gundam 00 are cruel deconstruction of this trope.
In the Cowboy Bebop movie, a convenience store robber takes an elderly customer hostage and demands that Spike and Jet drop their weapons. In an Establishing Character Moment, Jet drops his gun, Spike doesn't, takes aim at the robber and shoots him.
Mawaru Penguindrum has Asami Kubo, a young girl whom Kanba meets up with in episode 4. She's pushed down a metro escalator. She lives to tell, but ends up being given Laser-Guided Amnesia.

Literature

In the climactic scene of Harry Potter and the Goblet of Fire, Cedric Diggory is murdered simply because he happened to grab the Portkey at the same time as Harry (at Harry's behest). "Kill the spare" is one of the most chilling sentences in the entire series.

Live Action TV

In Buffy the Vampire Slayer the character of Jonathan is the go-to innocent bystander whom Buffy saves several times per season until he decides to become a super-villain himself.
- Wouldn't you?

Magazines

Mad Magazine once did a superhero parody with a character named, literally, Innocent Bystander, something along the lines of: "Officers! The jewel thieves went down that alley! You can easily head them off!" "You've saved the day again, Innocent Bystander!"

Newspaper Comics

An early Peanuts strip had Linus (then a baby who couldn't walk or talk) getting blamed for something, and another character protesting, "He's just an innocent by-sitter!"

Video Games

You do not want to be an Innocent Bystander in Fate/stay night. While the more "good" characters will fight at night and in remote locations to avoid involving you, if you do happen to catch them fighting and threaten to break their Masquerade? They'll kill you. Even if they aren't villains.
Civilians in most open-world games can be this, if they get caught in the middle of a mission, a car chase or violent rampage. Grand Theft Auto, Crazy Taxi, Saints Row, Postal, Bully... Some get it worse than others. You'll probably be alright in Bully and Crazy Taxi, but if you're a pedestrian in Postal and Grand Theft Auto, and the player's a cruel dick with a love for wanton destruction...well, bye.
Tourists in the game Evil Genius. If they see something incriminating or get trapped inside your base, they'll panic and raise the international heat on your operations if you don't...pacify them (said pacification can involve killing them, or simply pampering them until they're too confused to know which way is up).

Web Comics

The creator of Union of Heroes once invited his readers to become Innocent Bystanders of his photocomic by sending him portraits which were later included in the story.
In Sluggy Freelance the Main Characters are actually responsible (though usually accidentally) for quite a few Innocent Bystanders biting the dust. In fact, once two fans of the strip won the right to have a cameo appearance in the story. Pete Abrams, the writer/artist, honored this agreement, and had them crushed to death by Aylee.

Western Animation

The Yuppie Couple of Gargoyles, Margot and Brendan were frequently made innocent bystanders. It happened so often they even began getting snippy at each other when their ideas for a quiet getaway turn into a run in with monsters or kidnappers or robots or what have you.
- Likewise, the 1970's anime/manga Urusei Yatsura had Mr. Noodle and Miss Soup, who were always trying to have a romantic moment, but were constantly interrupted by aliens, demons, monsters, and teenagers rampaging through.
In the Darkwing Duck episode "Planet of the Capes" exactly one person on a certain alien planet isn't a superhero; he's named Normal Guy and the planet's superhero population devote themselves to protecting him. AND ONLY HIM. In the end he becomes a supervillain just to get them all off his back.
- If they're ALL superheroes except one guy, why would their society consider those shared powers "super" at all?