FimFiction Link - Short ID: 12540/star-gazing
Published: Feb '12 — Mar '12
NMM wakes up in Twilight and tries to make her evil.
The start of this story is really rough as there are a lot of misspellings and poor characterization. After two chapters or so, the misspelling seem to taper off. The oldfic tax is present: all of the M6 have to arrive and do their song and dance, they are just caricatures.
Through magical contrivance, Celestia and Luna are vaguely aware that something is wrong with Twilight and Luna arrives shortly after that for on-site monitoring. And there are a bunch of cute scenes with the two of them doing mundane things around the Treebrary. There is a big party with Pinkie as well, with amusing Appledash shipping. Twilight and Luna talk with each other about how much they appreciate eachother's hardships and do various lovey-dovey things like feed each other tea and sandwiches. Between all these events, NMM is seething impotently behind Twilight's perception, failing to convert her to evil while Twilight completely fails to notice anything except poor sleep quality. It's fun.
Then, NMM pushes a figurative button, inspired by Discord's cheating corruption of Fluttershy, and "deletes Twilight's morals." That's it. Now, she's mean. It happens right at the halfway point, and I dropped the fic here.