Some accidents are small, and some endow you with the power of a godly ruler. On the opposite end of things, you lose your wings along with your ability to move celestial bodies, and you can't tell anypony. Why, because what would they think if the princess became a librarian? It's going to be "fine". Celestia just needs to switch back with Twilight before either of their true identities are revealed. All Twilight has to do is hold down the castle, fight off scheming villains, run the country, and worst of all... deal with all the noble ponies.

Rated teen for shenanigans and some more serious parts. Takes place at the end of lesson zero. Please tear this apart with comments. I like criticism. Comment if you have issues, don't leave me with a mystery thumbs down.

Imprisoned on the moon, the Princess of Eternal Night passed the time in any way she could, usually plotting her revenge.

But when someone else finds their way into her prison, she finds a new way to pass the time, and soon revenge is no longer on top of her list.

She returns to Equestria, but she's not alone, and the Royal Family has a new member.
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A little something I wrote on a forum for a thread called Hogwarts Rejection Letters. As you may infer, it is a crossover with Harry Potter.

When Rainbow Dash finds herself lost in a new and unfamiliar village, she reaches out to a certain lavender-hued stranger for help. But to Twilight Sparkle, Rainbow Dash is no stranger; at least until she notice her strange new voice, a lack of wings, and a fondness of the word ‘darling’. Intrigued by the uncanny looks to one of her best friends, she decides to lend the newcomer a helping hoof, but things go from weird to weirder when Pinkie Pie happily announces that she too has met her lookalike. Twilight Sparkle and her friends take it upon themselves to find out the truth behind this mystery: who are these doppelgangers? Could there really be another Ponyville out there? And what does it all have to do with Discord’s lost legacy?

Cover art by AireDaleDogz (http://airedaledogz.deviantart.com/)

On a dark day, one may wonder: just what horrors lie beyond the veil of the heavens? What ghastly demons exist that could only spawn in a pony's dreams? What terror!? What blight in the face of all that is good!? What- wait, it's the Mane Six?

What sort of twisted reality contains a lycan Applejack, a vampiric Fluttershy, a ghostly Rarity, and a lich queen Twilight Sparkle, you may ask? Why, it's just the Nightmare Realm, existing one and a half dimensions below and above the normal Equestria, and they are sick and tired of Nightmare Night not living up to its name in the 'real' world.

However, are these nightmares truly nightmares, or do they just like a good scare? Why, it depends on who you're talking to! So sit tight, give way to fright, for coming soon is Nightmare Night!

Celestia and Luna are both suddenly reverted to their younger years. Centuries of wisdom and intelligence are muddled by confusing hormones and urges, and are forced off the throne thanks to a rule setting an age limit.

Can Celestia and Luna cope with being fifteen again?!

(Yes they can.)

What are their plans to reclaim the throne?!

(Hint: it's party like they don't care.)

Twilight used to think she could handle stress pretty well. The smartypants incident however proved her wrong. So she decides that when her friends aren't there she needs somepony there to help her through the stress.

So what does our lavender librarian do?

She creates an artificial intelligence.

After a mysterious and widespread spell causes ponykind to vanish, Fluttershy is left behind to cope with what the future has in store for her and the remains of Equestria.

In a matter of days, the once-prosperous nation begins to descend into a harsh and unforgiving place. While cities crumble around her, Fluttershy finds herself living in a land rife with dangers and heartbreaking reminders. With nopony to turn to, Fluttershy is forced to learn to fend for herself, discover what happened, and, if possible, find a way to reverse it.

Survivor Shy is an illustrated story following Fluttershy in the weeks after a magical cataclysm. While the last pony relives her past, readers are offered a vivid glimpse into Fluttershy's mind and are led on a harrowing journey through the ruins of Equestria and beyond.

Story branches out before Season 3 Finale.

In-progress Reading by Finish Line available
In-progress Russian translation by Papilion_star available.

For almost a year now, Trixie has been sending letters to Twilight. The only problem is, Twilight hasn't gotten a single one... until today. But now that she has, Twilight is left with more questions than she knows how to answer. Fortunately, she has a plan. Unfortunately, she doesn't know if that plan will work.

Featured on Equestria Daily
Reading by: WhoLandon
Reading by: PonyFicsOutLoud

Twilight wakes up with a serious head-ache caused by her horn spontaneously growing due to a sudden increase in her magical power. Nopony seems to have an answer for it, but it has attracted the attention of an unusually powerful militant foreign nation intent on her capture and execution. When a string of events lands Twilight before Celestia's father himself he tasks her and her newfound magic with tying up some loose ends he'd left behind long ago, ultimately connecting with this foreign nation's goals. With their powerful enemy baring down on Equestria, intent on taking it in a stranglehold, Twilight and her friends have little other choice than to travel the world and hunt for the rest of Celestia's family and end several thousands of years worth of feuding to prevent the war coming to Equestria before they themselves are caught.

Image Picture by Lostzilla of DeviantArt.
(find him yourselves)

Ech is a whiny bitch, but he helped edit a little I guess. (you too bats)

CLAMP and MLP:FiM crossover.

Twilight Sparkle discovers a strange book from her uncle's collection, and accidentally releases a powerful force known as the Clow Cards. Now, she must become Cardcaptor Twilight, and recaputre all of the cards, before a great catastrophe befalls the world.

Meanwhile, Yuko Ichihara has spotted her chance to finally claim the prize she has always sought from her biggest rival, but is unable to capture the Clow Cards herself, due to certain limitations in her powers. Therefore, she leaves it in the hooves of one of her customers, who, like Twilight Sparkle, carries the blood of Clow Reed in her veins.