Gideon is? a young boy who owns the "Tent of Telepathy", a successful competitor of the Mystery Shack. He has an unhealthy obsession with Mabel, and thinks Dipper and Grunkle Stan are the only things keeping them apart, when in actuality she has no interest in him. He previously had an amulet that gave him telekinesis, but it was destroyed by Mabel after he attempted to use it to kill Dipper. It is shown that he owns the book marked 2, the previous volume of the book Dipper owns marked 3. His new mission is to gain possession of the Mystery Shack.