The Diamondium Cannon is a cannon in the sphere-like part of the Planet Express building. It detaches from the rest of the building, connected with a metal tube. Diamondium is fired from the part of the building. This bizarre invention was once used to try to fight one of Yivo's tentacles, but it just bounced off the tentacle. This led Wernstrom to suggest using Diamondillium, but this did not work either.