"Celestia, I - don't understand. What's going on?" Twilight asked, voice shaking with anticipation of the answer. Celestia opened her eyes, irises flicking back and forth between raging orange and peaceful violet. "I have fallen," she replied.
An egg had laid dormant in the Everfree Forest for centuries, basking in magic that it had never experienced before. Then White Lightning disturbed it, and the creature - the xenomorph - inside was awoken.
Twilight likes books. Twilight knows that not everyone does, but Twilight knows that everyone loves knowledge. So, the obvious conclusion is a short guide to her favourite subject, yes?