Princess Twilight Sparkle, fearing the rise of a new villain, uses the time travel spell once again to return to the desolate landscape she came across in her stand-off with Starlight Glimmer. Her mission: to gather any evidence she can pointing to the evil that succeeded in destroying Equestria.
Twilight will learn, however, that good intentions can be the birth of malevolence.
The end hit me.
7684918 Excellent. Have a Hellish Halloween!
Revenge of the paperclip optimizer.
Just don't make it then.