Experiment 210/The Shape Shifter

(voiced by Mark Hamill) - A monstrous creature presumably created by Stanford "Ford" Pines. After his escape of his cryogenic chamber, he takes the form of a man that promoted cans of dog food. After he meets Wendy and Dipper, he steals the Journal 3 and tries to escape with them, but finally, he is locked again in his cryogenic chamber by Dipper, Wendy, Soos, and Mabel. A flashback revealed Ford discovered the Shapeshifter hatching from an egg. "Weirdmageddon" implies he is a descendant of an alien creature brought onboard the UFO that crashed into Gravity Falls. Journal 3 reveals that Ford originally kept the Shapeshifter as a test subject for the cryogenic freezing device, but grew attached to it and kept it as a pet. Ford was eventually forced to freeze it after his attempts to get the Journals escalated to attacking and impersonating Fiddleford.