Megalon is a large cockroach/beetle based kaiju controlled by the Seatopians and the primary antagonist of the 1973 Godzilla film, Godzilla vs. Megalon.
Megalon was the guardian of Seatopia, an underwater kingdom, that suffered from the nuclear testing and pollution of the people in the surface world. They summoned Megalon to make the people pay by attacking Japan. The monster began wreaking chaos throughout the country but was soon opposed by a robot known as Jet Jaguar. The Seatopians had stolen the robot previously to help Megalon, but its owner had freed it from their control. Jet Jaguar was able to outmatch its foe and the Seatopians asked the Nebulans to send Gigan to help Megalon. The two were able to overpower Jet Jaguar and were close to destroying the robot, but Godzilla arrived and helped the robot drive the two away. Gigan fled back into space and Megalon burrowed back underground, where it has stayed ever since.
- Even though Godzilla vs. Megulon was a critical and financial failure, Megulon remains a popular character in the Godzilla franchise, being a playable character in multiple games, including Godzilla: Destroy All Monsters Melee, Godzilla: Save the Earth, and Godzilla: Unleashed.