The Scrappy...a character that is annoying, unloved by fans, despised by several authors, and breaks several bases.
Of course, YMMV, so sometimes the hatred is warranted, sometimes it isn't.
However, once thing is often forgotten when talking about Scrappies:
some Scrappies are there for a reason.
This trope covers all instances when the Scrappy performs a key role in the plot of the story. Removing the Scrappy means the story can't flow properly (often to the point when the story happens BECAUSE of the Scrappy's presence). So, as much as they fans hate the character, they have to put up with it in order to enjoy a story they like.
Right, so THAT is why she was so important...
Examples of Only Scrappy Can Return the Spirits to the Chest include:
- The Trope Namer is The 13 Ghosts of Scooby Doo. There, as per the rules of the Chest of Demons, Scrappy Doo is among the few that can sucessfully return the evil spirits to the Chest. As such, the character who named the trope about annoying and/or poorly received characters now has a key role in the story.
- The trope image refers to Captain Marvel and her role in the Marvel Cinematic Universe. She's so much a Scrappy that she is the former Trope Namer for Newcomer Scrappy ...but she's also one of the few (if not the only) superheroes strong enough to defeat Thanos in combat, thus being a key player in the narrative of Avengers: Endgame...that being said, she does very little in that film, meaning the lingering shot of Nick Fury's pager in Avengers: Infinity War didn't have nearly as much significance at it seemed.
- Jar Jar Binks, perhaps the only character who's an even bigger Scrappy that the Trope Namer himself, is a key character in the events of Star Wars. Not only does his presence kickstart the plot of The Phantom Menace, but him granting Palpatine emergency powers is what allows The Empire to be created.
- Paz Ortega Andrade is pretty much one of the most hated characters in Metal Gear Solid: Peace Walker largely due to her annoying emphasis on "peace" as well as her being a mole for Zero in one of the series' most twisted reveals. That being said, however, she was pretty much the main reason the game's plot happened, since if it weren't for her, MSF wouldn't even be in Costa Rica in the first place.
- On that note, Raiden in Metal Gear Solid 2: Sons of Liberty was hated outside Japan for effectively replacing Solid Snake, that and other reasons. However, aside from him being the main protagonist of the game, both Kojima and Quinton Flynn have indicated that his presence was necessary to allow for a rare third person perspective on Solid Snake, comparable to Watson and Sherlock Holmes.
- The entire plot of Blues Brothers 2000 happens because of Buster (who's so much of a Cousin Oliver that he provides the trope image on TV Tropes).
- Wesley Crusher, who is the former trope namer for the trope about Scrappies that are beloved by the author despite their roles as Scrappies, had quite a few episodes of Star Trek: The Next Generation when he was a key part of the plot.
- Chibi-Usa, the most notable example of a Cousin Oliver in anime, is Sailor Moon's Kid From the Future, and as such plays an important role in the story.
- Starlight Glimmer plays a key role in My Little Pony: Friendship Is Magic after her redemption (said redemption ironically being what made her a Base Breaker to begin with): she helped save Equestria from a Changeling invasion, she was a key part in Cozy Glow's evil scheme, and she even managed to give a Cooldown Hug speech to Juniper Montage.
- Skyler is key to the narrative of Breaking Bad for, ironically, the same reason that made her a Scrappy: because she shows the toll Walter White's transformation into Heisenberg is taking on his family, and serves as an obsctacle in Walter's journey From Nobody to Nightmare.
- Na'Vi, annoying as she may be, DOES genuinely help Link in his journey.