So... was there even any point to Twilight going evil at the end, besides maintaining the status quo for the sequel you're never going to do? Because it was really sudden and jarring, was given no explanation, and then just sort of went away.

Though I suppose if you're playing TV Tropes Bingo, you can cross off the Big Lipped Alligator Moment.

Also, isn't Fleetfoot a mare in Equestria?

7801328

... is she? Ah, maybe I got them confused with Soarin'.
7801183

Tvtropes ... Bingo? You, sir, have put an awful idea into my head.

I suppose I could explain it as being my headcanon that the crown in the first movie was going to turn anyone into a demon, because its magic wasn't going to be used right ... but that don't actually address the root cause of your point now of it being a BLAM in story, don't it?

...Not seeing how the crown's rightful owner getting it back would lead to her becoming a demon to begin with, especially given it's an Element of Harmony. Perhaps if it were something related to the bimbofication magic and it not mixing well (the stuff was coming from Discord's counterpart, after all)?

Well, I'm happy to see that this turned out better than Less Common Superpower, and it certainly was an interesting read. I especially enjoyed the Lampshading of things throughout the story

"Do you know what this means, B.B? It means nothing can stop me now!"
"Nothing?" Beauty asked.
"Yes, nothing!" Sunset said.
"Are you sure about that?"

had to

"Hmm." Sunset dropped Applejack, letting her fall into B.B's chest. "I don't know... there's just something about....(this)…. that's just not good enough."

"Anyway..." Beauty held up the pocket watch, gathering Twilight and her friends together in one place. "Twilight Sparkle, if I could...(have…. the trinket you used when you were trying to cure me from Fluttershy?"

"Twilight... maybe things are different on Equestria, so this might be hard for y'all to understand ... but she was kind of mean, and she did do a lot of bad stuff. And that means she's gotta pay for it somehow. We got a sayin' 'round here - she did the crime, now she has do the crimes. (time)"