Substitute Harmony

"Substitute Harmony" is a multi-chapter fanfic of My Little Pony Friendship Is Magic by Blayze Kohime.

Plot synopsis: A strange group of ponies (who just happen to be main characters from the original G1 My Little Pony series) attempt to kidnap the Mane 6 with the apparent intent of stealing the Elements of Harmony. Pinkie Pie is the only one that escapes, and is briefly blamed for the commotion due to a misunderstanding.

Her sisters, Blinkie and Inkie, arrive to help, wrecking Ponyville town square in the process. The events also bring Trixie and Gilda to the town, for various reasons. Oh, and Ditzy's here; she's brought you a letter. When the circumstances end up pushing them all into a group, they are forced to work together to find out where the strange other-worldly ponies have come from and what dark force is leading them.

Read it here.

Tropes used in Substitute Harmony include:

0% Approval Rating: The reason for Helios' initial banishment; his subjects were rather harsh.
Abnormal Ammo: Pinkie Pie's 'cupcake cannon'.
Axe Crazy: Surprise. Sweet mother of mercy, Surprise.
Batter Up: Surprise's Weapon of Choice is a baseball bat. In her first scene, attacks Mrs. Cake with it, beating her unconsious while laughing the whole time.
Big Bad: Helios
Bigger on the Inside: Pinkie Pie's saddle bags and the TARDIS
Chekhov's Gun: The amulet that Twilight Wish is wearing in the initial scene turns out to hold a corrupted Rainbow of Light that can be used as a weapon
Conservation of Ninjutsu: The Mane 6 are beating the G1 ponies in their first battle with them, but in the second round when only Twilight Wish remains for them to fight, she pulls out her Chekhov's Gun and decimates them.
Crap Saccharine World: The G1 world of Dream Valley became this.
Curb Stomp Battle: The G1 ponies set an elaborate trap for the Substitutes, only to get stomped once the trap is sprung.
Dark Is Evil: Averted. The Prince of the Sun from the other world is the villain, Luna, the Princess of the Night in Equestria, is good; as is her otherworldly counterpart.
Dead Little Sister: Helios' reason for becoming a villain.
Did You Just Punch Out Cthulhu?: Celestia arriving to restore order and getting her head blown off by Pinkie's friends. She got better.
Dull Surprise: Prince Blueblood is rather nonchalant at meeting Helios, even after almost getting tele-fragged by the latter.
Even Evil Has Standards: Helios attempts to spare non-combatants and goes out of his way to not 'technically' lie, even to his enemies.
- Though his "standards" don't keep him from brainwashing his minions as punishment for failure.
Everybody Lives: Even one character who was suppose to have already been dead.
Genre Savvy: "This is the part where the villain underestimates the hero and is soundly defeated, right?" Of course, both sides firmly believe the other side is the villain.
- Becomes Dangerously Genre Savvy when Helios who helped create the Elements of Harmony, gauges his actions to become immune to them.
Genius Ditz: Ditzy, especially when we learn that her 'special talent', bubbles, covers bubbles of all kinds - even space-time ones.
Giggling Villain: Helios briefly after he licks the crystal that contains Pinkie's Laughter element
- Surprise is of the Laughing Mad variant.
Ham-to-Ham Combat: Trixie and Twilight Wish get into this; Gilda complains about it.
Healing Factor: All alicorns, it seems.
Heel Face Turn: As is typical for MLP, every villain in the story ends up becoming good after their defeat.
Heroic Sacrifice: Oddly by Helios, via throwing himself into the time rift to save Selene. He didn't die, but he thought he would.
Lampshade Hanging: Per his Genre Savvy nature, Helios is fond of this. For instance when he breaks a truce and attacks Luna:

I know this is stereotypically villainous of me, but...think fast! (blasts Luna with magic)

Madness Mantra: Quoth Surpise, while clobbering Mrs. Cake with a bat: "NO WITNESSES! NO WITNESSES!!"
Mind Rape: Helios' 'conditioning'.
Noodle Incident: Whatever happened between Helios and Doctor Whooves at some point in the past.
- This is not the first time that Ditzy has been involved in the accidental release of a banished villain from its imprisonment.
- Also whatever the 'grounding' was that Blinkie and Inkie referred to.
Reverse Polarity: Ditzy advises Trixie to reverse the polarity because it always works.
Sealed Evil in a Can: Helios Though slightly different in that he wasn't exactly evil prior to being sealed; rather the being sealed itself made him evil.
Stable Time Loop: The substitutes end up waking up Helios in the past, causing him to attempt to kidnap the mane 6 in the future, which causes them to go back in time to wake him up to begin with.
Take Me Instead!: Luna attempts this after Helios captures Celestia.
Tele Frag: Helios attempts to do this to Luna
- Blueblood almost suffers this, but accidentally on Helios' part. Blueblood even uses the trope name.
The Dragon: Twilight Wish.
The Only One Allowed to Defeat You: Trixie's initial reasoning for wanting to help rescue Twilight Sparkle.
Utopia Justifies the Means: The G1 ponies are under the impression that they will get to live in a better society if they succeed.
We Have Reserves: Subverted, Helios will risk the success of his plan if he must to protect the lives of his minions like when he rushes to rescue Firefly and Surprise.