Nefarious's BFG was a location in Ratchet & Clank: Up Your Arsenal. It was a huge Ion Cannon. On Planet Koros Nefarious possessed a Robot Base, which was a city area occupied by his soldiers, the center of the Robot Base was a Command Center atop which stood the Ion Cannon. This important location served as a refueling center for the Biobliterator, which was easily defended from attack by the Ion Cannon. However, Ratchet and Clank turned the defenses against the Biobliterator, striking a blow against Nefarious.
Behind the scenes
- "BFG" is an acronym for "Big F——ing Gun." 
- Ratchet & Clank: Up Your Arsenal (first appearance)