Gynagamoth is a three-eyed green moth monster who based himself in a cave for his experiment to revive the deadly Gaina Moth from extinction, altering their venom so the infected would have an hour before mutating into humanoid Gaina Moths. He could fire ultrasonic waves from his head feathers that can blast through rock, has a whip-like tongue, and has sharp claws on each hand. When Reiko, her teacher, Shigeru and his friends stumbled into it they end up trapped within the cave and poisoned as a result. Kohtaro attempts to deliver the cure with Gynagamoth attacking him. Using Rideron to hold off Gynagamoth, RX managed to kill him with the Revolcane, causing the revived Gaina Moths to die out as a result. He then managed to cure everyone after Gynagamoth was destroyed.