Bill Cipher is a dream demon, which means he can enter anyone's subconsciousness and view all their thoughts/memories. He is summoned via an incantation that must be spoken, which can be found in the journals. Gideon is the person who summons him and sends him into Stan's mind, in an attempt to take of The Mystery Shack. Bill agrees to help Gideon, upon realising it's Stan.
After failing, he has seen later in season 2 and tries to stop Dipper from discovering who the author is.
He is mentioned in the 3rd journal that Gideon has, where it is scribbled in red ink "Do not summon at all costs!" in capitals.
|June 14, 2015|
|the gay agenda|