The PlanetBuster Maximus was a giant rocket built in Hoven's Bomb Factory meant to obliterate the planet that occupied Chairman Drek's new planet's ideal orbit: Veldin. While it was being carried away from the Bomb Factory by a massive starship, Ratchet and Clank were able to use a small turret to obliterate the vessel, sending the PlanetBuster falling into the icy waters below. The idea was succeeded by the Deplanetizer.
The ship carrying the PlanetBuster Maximus could only be fought using the nearby turret. Ratchet would need to aim at each section of the ship to slowly destroy it. Five turrets on the ship would fire upon Ratchet and Blarg Rocket Helicopter Commanders would also appear. After destroying each section of the ship, the PlanetBuster Maximum and it's carrier would fall harmlessly into the ocean.