Marco was stretched out on a hard chair in a beat-up DeKalb County school conference room, in the presence of a former teacher who's taken up for him.

Alex Hirsch talks about Bill Cipher, Summerween, Gravity Falls, and which character deserves a 50 Shades of Gray-style spinoff. The Book of Bill is out now.

But Bill Cipher, the inter-dimensional demon bent on taking over the multiverse, is back in action — or at least, he’s back in a new book penned by Gravity Falls creator, Alex Hirsch.

Gravity Falls’ big villain, Bill Cipher, is getting his own book written by series creator, Alex Hirsch. And it’s for older readers! Out in July.