So anyway, this pony, right? Bitty Thaco? She came into my library, Applejack. I know, hold on, I'm getting to that part. Just sit down and let me tell the story. You know how much I envy Bitty. Being the sole object of attention for so many handsome stallions must be a dream come true. So when she came into the library asking for help with a sex contest, I knew just what I had to do. I had to cast my special patented Dinosaur Dick-B-Gone spell at the dinosaur. The rest of the contest would have been trivial, because I'm sure Bitty gets a lot of practice at the whole sex thing. I got Spike to get my custom spells scroll, where I had written down the instructions to cast the Dinosaur Dick-B-Gone spell. I have to admit, I never expected to actually get an opportunity to see the spell in action. Dinosaurs are extinct, you know, and I can't pass up an opportunity to study an extinct creature and zap its penis away with magic. After all, they don't call me Twilight Dick-B-Gone Sparkle for nothing. Unfortunately, it turns out that dinosaur penises are actually immune to magic. Dinosaurs themselves probably are, too, but I didn't get a chance to test magic on the dinosaur’s non-penis parts. And dinosaur testicles seem to be capable of catching and redirecting magic. That's why every pony in Equestria is now without a penis. I'm sorry Big Mac is upset, Applejack, but it should be clear to you why I did what I did, and I hope you can forgive me.
This is my favorite part.
Also the other parts.