The Light in the Darkness - Television Tropes & Idioms

A My Little Pony Friendship Is Magic Fanfic written by zaptiftun.

After spending the day in Cloudsdale at a Wonderbolts air show and even getting to spend some time with her heroes, Rainbow Dash heads home content that she'd had one of the best days of her life. That is until she hears a terrible scream coming from her friend Pinkie Pie's house and enters to find the pink Earth Pony nearly broken by a horrific nightmare. Rainbow Dash must now help one of her best friends overcome some serious inner demons and get back to her happy, normal self.

The Light In The Darkness is considered by many to be one of the most heartwarming fanfics in the fandom and quickly became extremely popular on both deviantART and Equestria Daily. Despite being a one shot and relatively short, it's gained a reputation for being heartwarming enough to neutralize reading the infamous Cupcakes fanfic. It was originally intended to be another Alternate Ending for Cupcakes but was revised to be more of a stand alone story though there's enough vagueness with Pinkie Pie's nightmare to still consider it as one or just a stand alone. It's also considered a great example of a "Friendshipping" story, depicting the characters' love for each other as completely platonic but still very real.

A live reading can be found here.

This My Little Pony Friendship Is Magic Fanfic contains examples of provides an example of the following tropes:

Adult Fear: Rainbow Dash trying to find Pinkie Pie, believing someone has broken into her house and may have done something to her.
A Friend in Need
All Just a Dream: If you consider this an Alternate Ending to Cupcakes, then the events of that fic. Regardless it begins with Pinkie Pie suffering a horrible nightmare.
Alternate Ending: Was originally concieved as one to Cupcakes. It was changed when the writer realized just how many of those were around, but the events of the nightmare are vague enough to still view it as one if you want to.
Ax Crazy: Pinkie Pie is terrified this may be true of her. Subverted ultimately.
Break the Cutie: Pinkie Pie's nightmare pretty successfully did this to her. She gets better.
Cool Down Hug: When Pinkie Pie starts to slip back into her Heroic BSOD, Rainbow Dash uses this and some words to pull her out of it.
Enemy Within: Pinkie Pie believes this may be true of her. It turns out it's not but it takes a lot of convincing.
Gosh Dang It to Heck!:
Rainbow Dash: Why the hay does a bakery have a cleaver?!
Heroic BSOD: Rainbow Dash comes upon Pinkie Pie in the midst of very serious one. Rainbow Dash uses this to convince Pinkie Pie that she's not psychotic because she had this reaction to the dream.
Madness Mantra:
Pinkie Pie: Can't let it happen…have to protect friends…won't let them die.
Noodle Incident: Apparently the Cakes are not at Sugercube Corner because they're on vacation to help Mr. Cake recover from getting a Twitchy Eye in response to Pinkie Pie performing an experiment involving pies and popcorn.
Paranoia Fuel: In-Universe, her nightmare and the existence of "Pinkamena" are this for Pinkie Pie.
Shout Out: Pinkie Pie is a fan of the Marx Brothers.
Show Within a Show: Pinkie Pie's favorite show is explained to be My Little People.
Take Our Word for It: We never learn the full truth about just what happened in Pinkie Pie's nightmare, but considering what is said and how it sent her spiraling into a serious Heroic BSOD, it's much scarier that way.
- We also know that the story was supposed to be an alternate ending to Cupcakes, so we can make some guesses...
Thousand Yard Stare: Rainbow Dash finds Pinkie Pie in this state, noting her eyes are glazed over and, while she's focused on what she's doing, she just looks like she's in blind terror.
True Companions: Considered one of the best examples in the fandom for depicting the heroes relationship thusly.
WAFF: There's a reason this is known as the antithesis of Cupcakes.
Wham Line: Rainbow Dash, at least, gets completely blindsided by it. "Dashie, I KILLED you! I killed EVERYPONY!"
Who Would Want to Watch Us?: Pinkie Pie mentions she likes a show called My Little People. Rainbow Dash is amused that Pinkie Pie has an obsession with a "little filly's show".
You Have Got to Be Kidding Me!: Rainbow Dash has this reaction (at first) when she is told a nightmare was the cause of Pinkie Pie's Heroic BSOD. That changes very quickly when she learns just a little bit of what that nightmare was about. She also has this reaction due to the fact that the bakery for some reason has a meat cleaver.