This mecha paper model is Big Duo, the second Big from the animated television series The Big O, the papercraft is created by WebDude. The Big Duo is piloted first by Schwarzwald. Schwarzwald planned to use the megadeus to destroy Paradigm, using its flight capability to attack the domes, or "false skies" as he calls them.
It was found by Schwarzwald in a hangar to the south of Paradigm City, as revealed in a flashback in "Leviathan". Roger is able to defeat Big Duo by hammering it with repeated attacks. However, Big Duo still moves without a head or a pilot, and as a final act it reaches towards Paradigm City's center, suggesting a link with the domes or another potential pilot in the area. It is possible that the semi-sentient megadeus reaches for Paradigm HQ with the intentions of trying to carry out the wishes of Schwarzwald regardless of its defeat and crippling damage. R. Dorothy investigated the nearby area and found traces of Angel's presence.
Big Duo is the only megadeus possessing the ability of flight. Its propeller hands also served as blade weapons. Other armaments included optic lasers, machine guns in its forearms, missile batteries in its chest, and a pair of heavy missiles stored in its knees. Big Duo was also capable of producing a smoke screen. Due to its great speed and mass, it was effective at using its entire body as a battering weapon. It's diving punch was equivalent to a piston punch from Big O, and the two attacks canceled each other out. After being defeated, it was salvaged by Alex Rosewater for Big Duo Inferno. [Source: wikia]