Mary is mechanical in nature. Six articulated legs are affixed to the forward section of the vehicle in a spider-like manner, and seem to be its main source of mobility. The rear carriage of the machine boasts two large wheels, and between them, a seat on which Chariot sits when driving the vehicle. In the front of the vehicle is a construct resembling a large face, with a mouth that can open and close freely. From this mouth, the machine can launch oversized macaroons (one of the motifs of Chariot's other self, Kagari) like cannonballs. The entire thing is extremely large and fomidable.
The vehicle, despite being very large, is capable of exceedingly fast movement and can execute deft maneuvers. Its huge legs can crush an opponent and its wheels can deploy spikes to skewer pedestrians. Indeed, during their battle, Chariot used it many times to simply run Black Rock Shooter over. After being destroyed one wheel becomes Chariot's shield, while still retaining the ability to deploy spikes. The machine is capable of firing giant macarons at high velocities from its "mouth".