Author: The Psychopath
Description: During one of her many passion projects, Twilight decides to try and track down the origins of magic and where everypony came from. Her library is chock full of various different theories, none of them very helpful. She decides, instead, to ask Princess Celestia. However, the answer she gets is far more absurd than she bargained for. An answer so detached from reality that it takes a physical manifestation of it to show Twilight the extent of the terrifying source of magic and what it did to a once-benign world to render it and its inhabitants so fantastical. "You were never the first ones here, nor were you the second. We were the second."
The Sisters' Memory (Update Sequel)
Additional Tags: Familiarity in a past world