Twilight Sparkle: magic prodigy, agent of the Crown. Experimenting with a spell to use for covert operations, she gets an unexpected result, and an even more unexpected outcome.
Written for a "Twilight Sparkle's Secret Shipfic Folder" contest.
The ship in question is "Zecora" and "Zebra Super Spy Twilight", hence the "Alternate Universe" tag, and the shipping card was "So That's What That Does!".