Mutant fireflies, also known as mutant swamp flies, are enemies in Going Commando. They are small, yellow, glowing mutant fireflies native to Oozla, found in the Megacorp Outlet area, that are a cross between a firefly and a beetle. Ratchet encountered them during "Find the store entrance", "Investigate the Megacorp store" (in which they had infested the outlet itself), and "Explore the swamp ruins". They were often found alongside the mutant muckdweller and mutant swamp beasts.
Mutant fireflies are found in groups, and will circle an area before being approached. Once struck down, their yellow glow will end as they fall. Mutant fireflies pose little threat, as they are slow, and can be defeated easily with a hit from any weapon.