Not sure when I'm going to post my cover art, so this one has to do for now.

When Rarity finds herself in a concrete room, strapped and chained to a wooden bench with nopony else other than the Apple family, she is shocked by their strange behavior. Especially that of young Applebloom, showing signs of bloodlust and hunger.
She only finds out her purpose and the Apples' origin after the full moon shines through a hidden window...