This gundam paper model is a SD transformable NRX-055-2, the 2nd unit of the NRX-055 Baund Doc, which is one of several transformable mobile weapon designs tested by the Earth Federation forces during the Gryps Conflict of UC 0087, the papercraft created by [unknown].
Despite its apparent size and bulk, the Baund Doc's half-egg-shaped Mobile Armor mode was very fast and maneuverable thanks to multiple vernier thrusters and apogee motors. The MA mode was equally capable of offensive and defensive operations, and it transformed into a non-symmetrical Mobile Suit form armed with a beam rifle and beam saber for standard one-on-one combat, as well as a powerful scattering mega particle gun mounted in its large left arm for attacking several targets at once. It was equipped with a Psycommu System, which allowed its pilot to more directly interface with the Baund Doc's operation. Although normal human pilots could operate this transformable mobile weapon, its true potential only came out in the hands of a genetically-engineered "Cyber Newtype" or a natural-born Newtype.
Three Baund Doc units were built, although only the first one, the NRX-055-1, was the true prototype model. It had a specially-designed cockpit that could seat two individuals, the pilot and an instructor. The second and third units were essentially the same as the prototype, except they were built with standard single-person cockpits and sported highly distinctive color schemes of blue, yellow and pink.
You can download this papercraft template here: