"Like two peas in a pod we did everything together!" sang Twilight in the season finale. But what if she was letting on more than everyone else knew? What if Twilight really was a pea?

There comes a time when the light must go out; but how do you know if you've burned brightly enough?

The Princesses find an alien creature barely clinging to life at the scene of a terrifying crash. Can the Combined Power of the Elements of Harmony save it, or more importantly, should they save it? Will the arrival of this strange creature tear Equestria apart?

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https://tvtropes.org/pmwiki/pmwiki.php/FanFic/Article2

Luna has had enough of Celestia's games, and has found the perfect means of revenge. Using a long-forbidden spell, she transforms her sister into little more than a small filly, all so she could pull the greatest prank ever. Unfortunately, she soon learns that before you fool around with dangerous magic, you really need to read the fine print...

A sequel can be found here.

Twilight Sparkle is accepted into Princess Celestia's School for Gifted Unicorns and gets a little more than what she bargained for.

Illustrated by me.

(If you object to swearing, please skip chapter 6. That's the one chapter that bumps this story straight up to a Teen rating.)