Mutant Fireflies, sometimes referred to as Mutant Swamp Flies, were a cross between a firefly and a beetle that had a faint gold glow. They were the only enemies on planet Oozla that did not live in the slimy water, but flew around small areas, usually in groups. The insects were often preyed upon by the flesh-eating Fly Trap plants found throughout planet Oozla. They attacked by flying up to Ratchet and pinching him with their pincers. They were easily killed by one strike from a Wrench. Also, while in large groups, Ratchet could slaughter all of them with the Gravity Bomb, or Mini-Nuke, with one shot. The Lancer would also take care of them easily. They would mostly only be considered a threat if they attacked in large groups; however, they were very slow. They also looked very similar to the desert dwelling Mutant Sandflies of Tabora; however, the Mutant Sandflies did not give off a glow, were far times faster than Mutant Fireflies, and often attacked in swarms of 10 or more.
- The term Mutant Swamp Fly was used to refer to Mutant Fireflies, as seen in a game of Galactic Chess, but this may have been because some people were unaware of their true name.
- The Mutant Fireflies were chess pieces in Galactic Chess.
- Clank stated while playing Galactic Chess that the Blargian Snagglebeast was allergic to the Mutant Fireflies. The Blargian Snagglebeast was affected by the allergic reaction for two turns in the Galactic Chess game.
- Ratchet & Clank: Going Commando (first appearance)
- Ratchet & Clank: Up your Arsenal (mentioned only)
- Ratchet & Clank Future: Tools of Destruction (mentioned only)