Actually, better idea. He does it Dragon Ball style and his weapon was made by CAPSULE CORPS! Another family owned conglomeration, but instead of controlling dust they handle functional but disposable weapons for hunters an militias. Normally their [Capsules](http://dragonball.wikia.com/wiki/Capsule), small devices in the shape of pills, look unassuming and fairly useless. But once activated and detects that it has an appropriate amount of space (so it can't go off if they are, say, put into a small box) they can turn into almost anything it has been designed to contained short of a house. Most however cannot be changed back to their capsule form, however perhaps this tank would be a prototype model testing this out, and the reason Marcus has it because he's the son of the lead developer within corporation, henceforth known as The Goldstien Standard Conglomerate until a better name has been made.