A maker built a real, functional replica of the arm cannon belonging to Vandal, a character in Bungie's upcoming game Marathon, for use in a commercial. The builder had 18 days to complete the entire project.
The build was divided into two main subsystems: a forearm clamshell mechanism and an internal barrel assembly. Bungie provided game asset mesh files for reference but, because the files were hollow, all internal components had to be built from scratch. To open and close the clamshell, the builder used scissor lift mechanisms milled from cast ABS plastic on a CNC machine, driven by linear actuators rated for 50 lb of force. The remaining four motion sequences were actuated by a single motor using a rack-and-pinion assembly. The wrist mechanism, described as the most challenging component, was solved using flexible TPU bands to mimic dorsal carpal ligaments, while the hand was reprinted in foaming TPU to cut its weight by nearly half. Because the commercial was to be filmed hidden-camera style with unsuspecting members of the public, the prop had to survive a 4-foot drop onto concrete. The test destroyed one linear actuator but left all other components intact. The builder purchased 10 spare actuators and began printing a complete second arm as backup.
On set, the builder collaborated with Jesse Velez of Raptor House Effects, who oversaw all builds for the project, including two full game-accurate character costumes. A hidden solenoid was added to simulate recoil. The arm's trigger was synchronised with a wall demolition rig, allowing the explosion and arm cannon to fire as a single timed sequence. The shoot destroyed more than two dozen walls without the arm cannon ever failing.
