Paper is a mouse and a member ex post facto of H.A.L.O., as well as partner and best friend of Plastic.
Very little is known about Paper, because her story as Plastic remembered it was itself amalgamated when the Darkfox and Happy Forest universes merged. In the Darkfox universe, Paper and Plastic were a superhero team, young and cocky. While fighting an unspecified villain (Plastic remembers it being Ironhorse) they were trapped and Paper was killed while Plastic, unable to help, was forced to watch.
In the merged universe, Paper was manifest as an insubstantial semi-tangible entity similar to a ghost or someone out of phase with the rest of the dimension. She could not be perceived by everyone, but Plastic determined she was real by having her read something he had not looked at yet. His best guess was that Paper had yet to exist, as if by being merged her death had been reversed.
After the HALO universe was recreated, Paper reappeared fully alive in her merged anthropomorphic form.
Paper has psychokinetic control over wood products, especially paper, and can move other objects, such as a cash register, by pushing them with the paper. This power can technically extend to any formerly living material, but for an unknown reason, the more highly processed the material is, the better it responds to her powers. Thus, paper is optimal. Her weakness is the absence of any trace of wood or wood product, as her small stature and constitution are easily outmatched.
In general, Paper is headstrong, impulsive, and excitable, but she is also caring and optimistic. Her sunny disposition offsets Plastic's more pessimistic outlook.