Season 1, Episode 8. “Look Before You Sleep”
 
It was a rainy and cozy night, perfect for a curl up and good read in a quiet library.
 
Aside from the lightning striking nearby, Spike was confident he wasn’t going to be bothered by much else. None of Twilight Sparkles schedules or lists mentioned anything about needing the closet off of the main foyer of the library for at least two more weekends, so it was a sure thing that she would stay out of there. “Official Business in Canterlot” is Spike’s personal code for “I just need a weekend to myself!” It was a foolproof plan! He hung a “Do Not Enter” sign on the door, just in case. (hey don’t question it, it seemed to work!) He could have gone anywhere, but since rain was scheduled, staying at the library seemed like the easiest of all the plans.
 
But then something unbelievable happened, Twilight threw a slumber party! Knowing Rarity was going to stay the night didn’t help.
 
After the first round of bickering flowed from the front room, Spike nestled down to get comfy again when suddenly the voices rose again, some soft thuds from the next room could be heard, and before he knew what was going on, a pillow came flying thru, knocked the door wide open and ..
 

 
Luckily Twilight was too distracted by her guests to notice the door to the side room slowly creak to a close.