A strange creature with squid-like body and eight spider-like legs, the Fire Monster was able to surround itself with a "second body" made of flame, and fed on fire. H.E.A.T. encountered this creature while exploring a damaged oil rig in the Gulf of Mexico, when it was feeding on the fuel from the rig. However, as Godzilla attempted to destroy it with his heat ray, it simply fed on it and grew larger, eventually growing to twice Godzilla's size. H.E.A.T. managed to cut off the creature's fuel supply, and it shrank back to the size of a bus.
However, Dr. Craven and Randy saw the potential in discovering the creature's process of regenerating energy, and smuggled the creature back to the HQ. But the creature revived, and nearly burned down all of Staten Island. Finally, it was caught and trapped in a vacuum bubble and sent to the bottom of the ocean. But at the last moment a shark damaged the container and apparently released the Fire Monster.