Board Thread:General Discussion/@comment-28799866-20151223095349/@comment-27101167-20160115031937

Queen Desi wrote: There actually is a wizard in the closet in Mabel and Dippers room and he's the one whose been making all the strange things in Gravity Falls occur. He also is the brother of Bill cipher. They went to college together as well and got into a fued. Which is why Bill is evil.

I think its canon that the Invisible Wizard is Bill