The story will be called "autocorrect," and will future Twilight attempting to fix Rainbow Dash's grammatical errors (in her speech) by casting an autocorrection spell on her. This backfires as she gains Apple's infamous conversation killer. The autocorrects will be random autocorrects that occur while writing the story.

1693099

The foggy who?

1693099 Make it random, and you've got yourself a hit.

1693099 Could have potential.

1693236 Of course it's going to be random.
Rainbow Dash will be talking to someone and this will happen:

"So, did you see that huge cock I did yesterday?" Instead of "huge trick" and it'll be like

1694560 ..... Followed.

1694719 thanks :D