On a patrol through the White Tail woods, Twilight comes across a dying changeling. Torn between giving up the drone to the guards or leaving it in the inhospitable wilds, Twilight reluctantly takes the drone in. As it awakens she realises that the drone was a blank slate, with no connection, no 'programming' guiding its functions. So Twilight sets out to teach this changeling about the world, one hoof step at a time.

Rated Teen for slightly mature themes involving ethical dilemmas.

If Word Worthy stopped editing for me, I'd likely wind up as a grammar-less hack. Thank you, thank you, thank you!

Twilight Sparkle conducts an experiment and succeeds in obtaining an unusual flower with some intriguing properties.

What it could teach her, however, might prove to be more than she bargained for. She finds herself having to face surprising—and maybe frightening—new possibilities about the universe. How does it work? What is 'real', exactly? And why are these suddenly such uncomfortable and challenging questions for her?

Pre-reading and editing for this story was done by Grand Moff Pony, The Dobermans, SIGAWESOME, Reese, Georg, LCranston, and Equestria Daily pre-readers 63.546 and Slorg. Many thanks to all of them for helping this get where it is!

Now with an audio reading by TheDizzyDan!

After a fall and a blow to the head, Lyra begins to have hallucinations that she's a young human girl in mental hospital. As she flashes back and forth between the two, medical personnel in each do their best to cure her of her delusions. But as the day wears on Lyra begins to question which world is real and which one is only a mental construction. How can she pick one world, when they both seem so convincing? And what happens if she chooses incorrectly?

PRINCESS TWILIGHT SPARKLE: DEAD AT 18

TELEPORTATION INVARIABLY FATAL, WARNS LEADING SCHOLAR

One look at the headline of the Canterlot Times and Twilight knew that she should have slept in today. But at least none of her friends would be silly enough to believe she was killing herself every time she teleported, right?

There is now a Spanish translation of this story, courtesy of Spaniard Kiwi

Princess Celestia has been keeping a dark secret from her subjects for a very long time.

It's not an easy truth to tell, but if anyone can accept her after learning it, it will surely be her most faithful student.

Third Place Finisher in Equestria Daily's 2013 Nightmare Night Contest!

Daring Do cannot believe her luck when she is asked to help explore the most ancient tomb known to ponykind. But terrible danger awaits her, for beneath the earth rests something beyond equine understanding.

Warning: comments contain ending spoilers.

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Alternate ending by Duplex Fields.
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Twilight Sparkle’s own body has betrayed her. Her life hangs by a thread, and her only hope of survival is a vital organ transplant. But when the sole possible donor turns out to be a young, healthy, and honourable pony, Celestia proves just how far she is willing to go to save her student.

In the decision to trade one life for another, the most serious casualty may be everypony’s ethics.

Princess Celestia’s School for Gifted Unicorns is famous across Equestria as a center of academic excellence. Only the best and brightest unicorns are offered places, selected by their academic merit, magical ability and passion for study. To make the admissions process as fair and reliable as possible, all candidates are given three exams by different teams of examiners, who then meet in private to decide which students are most deserving of a place.

Winner of the December 2014 Writeoff competition: Behind Closed Doors.

It finally happened as Twilight always knew it would. The first of her friends had died. The Element of Loyalty too. Not loyal enough to stick around. No, that was the depression talking.

And the lack of sleep. Something was prowling the halls of her castle at night and, for some reason, she was the only pony that ever heard it; although, one guard did mention something strange happening to the lighting once.

It could not be ghosts. Their very concept made no sense. Intangible yet able to hear? What a contradiction.

But just in case…

Twilight's relentless study of Pinkie's strange abilities leads to a horrifying revelation.

This site really needs an existential horror tag.