Shape Shifter (Gravity Falls)

The Shape Shifter is a shape-changing monster from the cartoon series Gravity Falls. Appearing in the Season 2 episode "Into the Bunker", it was discovered by the Pines twins, Soos and Wendy Corduroy when they discovered Stanford Pines' bunker hidden in the forest near Gravity Falls.

History
The Shape Shifter had hatched from a mysterious egg that Ford Pines had discovered in the forest. For some time, Ford had studied the creature - labelling it Experiment #210 - in his underground bunker, monitoring its growth and its shape-changing abilities. However, the creature became too cunning and dangerous, so Ford attempted to build a cryogenic stasis capsule to seal the creature. The Shape Shifter managed to escape from its confines, but Ford was able to evacuate his bunker and seal it behind him, trapping the monster underground with nowhere to go.

Decades later, Dipper and Mabel Pines and their friends Wendy and Soos found the entrance to Ford's bunker. Investigating the bunker and surrounding caverns, the group are divided. Dipper and Wendy encounter a middle-aged man wandering around whom Dipper assumed was the author of the Journals. However, while the team are wandering the caverns, they find a discarded can of beans displaying the "author" on its label. It is then that the "author" turns on the group and attempts to steal the No. 3 Journal from Dipper so that he can examine all of the potential new forms within its pages.

After running into Mabel and Soos, they formulate a plan to get rid of the Shape Shifter. Dipper, Mabel, and Soos blast a jet of water at the creature, accidentally hitting Wendy. The jet temporarily stuns the Shape Shifter, but it attempts to trick Dipper by taking Wendy's form in one last effort to steal the journal. The Shape Shifter attacks Wendy, and Dipper becomes confused by who is who, asking the real Wendy to give him a sign. When the real Wendy zips her lips, Dipper hits the Shape Shifter with Wendy's axe, and the two of them push the monster into the stasis tube to freeze it. Before becoming completely frozen, the Shape Shifter gives Dipper one last warning about prying too deeply into the mysteries of the town and the author, saying it will end with a fate that is worse than he could imagine. It then mocks Dipper one last time by assuming his form and screaming as it freezes solid.

Personality
The Shape Shifter is a cunning, quick-thinking and manipulative creature. Without even knowing Dipper, Wendy, or their quest for the author, it was able to effectively set up an elaborate ruse to win their trust and gain the journal.

Appearance
In its true form, the Shape Shifter has a somewhat insectoid body, but it is misshapen and covered in translucent white flesh like a larva. Its left arm is short with a grotesquely swollen shoulder while its right arm is long and slender, ending in three digits. Its oval-shaped head sports two pink eyes and a circular mouth with flat teeth on the inside, but four sharp mandibles surrounding it. Its tubular torso ends in four slender legs like those of an insect.

Abilities
As its name obviously suggests, the Shape Shifter is capable of assuming different forms and can take on the shape of anything it has seen. It is also capable of assuming composite forms, merging two different forms into one. As well as altering its physical form, the Shape Shifter can also imitate other people's voices perfectly. It possesses superior strength to a human and is capable of crawling over walls and ceilings.