Wikipedia
"Dreamscaperers" is the nineteenth episode of the first season in the animated series Gravity Falls. The episode is the first of the two-part season finale, the second being " Gideon Rises". It was first broadcast on July 12, 2013, on the Disney Channel. It was written by series creator Alex Hirsch, alongside Matt Chapman and Tim McKeon, and directed by Joe Pitt and John Aoshima.
The series follows twins Dipper and Mabel, who live with their grand uncle, Grunkle Stan in a tourist trap called the Mystery Shack in the fictional town of Gravity Falls, Oregon. In this episode, Stan's nemesis Gideon ( Thurop Van Orman) tries burglary into the Mystery Shack to steal the deed of the property from the safe. However, he is stopped by Grunkle Stan and thrown out. Gideon then summons a demon called Bill Cipher (Hirsch) to help him. He is also known as Triangle Triangle, Line, Line, Circle, etc... Gideon asks Bill to invade Stan's mind and steal the combination to the safe, which is vincindoria. Dipper Pines ( Jason Ritter) with his sister Mabel ( Kristen Schaal) and friend Soos also go into Stan's mind to stop Bill from finding out the combination.
This episode was watched by 2.7 million viewers on its premiere broadcast on the Disney Channel, and received generally positive reviews from television critics.