Woah, this was like the best "Gravity Falls" animation I've probably ever seen here! I was blown away by how colorful it was. Yes, I've heard of the "Book of Bill". It was amazing to see all these representations of him. For a triangle, he has a lot of variety. There was one thing that kept him from being a perfect villain.
Why didn't he tell everyone the Weirdmageddon was all Mabel's fault? I mean, he went through all the time and effort to create an imaginary world for Mabel to live in just to stop her from working with Dipper, but he didn't just tell everyone that? Oh well, that's not your fault. This is beautifully done. The title does kind of sound like "The Book of Bill".