Deep within the heart of the West African nation Nigeria, a winged mutation was born. The Giant Bat originally attacked farmers and cattle in West Africa, but when H.E.A.T. showed up, the Bat was ready for them. As Zilla chased the bat into a nearby city, they were both soon consumed by their brawl. Using his high frequency, the Giant Bat escaped the reptile’s wrath, but a prior immersion in water had severely weakened his radar. Soon, Zilla and the Giant Bat returned to battle, and while Zilla was stuck in a bridge, the Tachyons, an alien raced covertly engaged in conquest of Earth, gained control of the bat and guided him back to Site Omega. As H.E.A.T. followed, they managed to foul the bat's radar with their own, causing him to attack Cryptocleidus, a cryptid inhabiting a nearby lake. The aliens regained control of the bat, and both came ashore on Site Omega.
The aliens then commanded the bat to attack Paris with King Cobra. As the beasts attacked the French city, the monsters soon broke free of the Tachyons' control and the bat returned to Site Omega, attacking the alien fleet. The aliens called Cyber-Zilla to their defense and the two did battle, but the cyborg Zilla proved too powerful and the Giant Bat was knocked out. After the war, the Giant Bat was restrained and left on Site Omega, which would become Monster Island.
A few months later, the organization S.C.A.L.E. freed the monsters of Monster Island, including the Giant Bat. He faced a few monsters before being recaptured and returned to his area of the Island.
In an alternate future where the D.R.A.G.M.A.'s took over the earth, the Giant Bat was killed along with the other monsters of Monster Island.
Giant Mutant Vampire Bat
The Giant Mutant Vampire Bat, or a similar creature, was briefly mentioned in the episode Underground Movement. Most of the H.E.A.T. team had to go to Florida to settle a lawsuit for the damages that were caused while Zilla fought it. Fortunately, the suit was thrown out and H.E.A.T. returned to their mission.