The Void

To save Twilight, Starlight casts and ancient spell and uncovers a horrifying truth.

After Twilight goes into an unexplainable state of hysterics, Starlight, on a mission to help save her friend discovers a spell which may save Twilight but also brings with it a horrid fate to anypony who casts it.

A submission for RockstarRaccoon's Nightmare Night in April: Horror Write Off