Pearls Before Swine creator Stephan Pastis recounts how he was allowed the honor of having the reclusive comic legend guest-draw three strips last week.

Let me tell you. Just getting an email from Bill Watterson is one of the most mind-blowing, surreal experiences I have ever had. Bill Watterson really exists? And he sends email? And he’s communicating with me?

But he was. And he had a great sense of humor about the strip I had done, and was very funny, and oh yeah….

…He had a comic strip idea he wanted to run by me.

The full explanation of how it all happened is a great read and is available on Pastis’s blog. The strips Watterson contributed to as “Libby” are here, here, and here.