Prototype

Collecting the bodies of deceased characters—Prototype uses their remains as raw material to create new toys. This can be interpreted as:
Experimentation and Creation of New Creatures - Playtime Co. was dedicated to creating human-toy hybrids, and Prototype, being their most advanced experiment, could inherit this goal.
Self-Enhancement - The Prototype may integrate body parts into itself to repair or enhance its abilities.
Evidence Destruction - By removing the bodies, he hides traces of Playtime Co.'s experiments, although this version is less likely, as the Prototype acts independently and is hostile to humans.

Character
The prototype is described as a cunning and intelligent creature. It possesses excellent problem-solving skills, agility, analysis, and intelligence.

Some of the Prototype's abilities:
Body Control - Can use various appendages of his body.
Absorption and Mimicry - The Prototype appears to be able to assimilate other talismans into its mass.
Self-sufficient - does not appear to require food or rest.

The Prototype's appearance hasn't been fully revealed yet. Some features mentioned in the game include:

The left hand. The fingers resemble thin silver pins, apparently capable of a wide range of motion. The forearm is adorned with red wires and metal fittings, and contains the radius and ulna bones.
The lower body has characteristic arachnid features: six large legs covered in durable metal, apparently reminiscent of a scorpion's tentacles, connected by cables at each ligament.
By the time the Player returns to the factory, the Prototype has grown in size, presumably due to the creation of a new body composed of parts of dead toys.