Megatron is the leader of the Predacons. His beast mode is a fearsome Tyrannosaurus Rex. His ultimate goal is to conquer Cybertron, where he was branded a criminal. He has also had a rivalry with Optimus Primal, the leader of the Maximals. He later became a Transmetal and then a Transmetal 2, in which his beast mode became a Dragon. And later he became Optimal Megatron at the end of the Beast Machines.
Optimus Primal vs. Megatron Edit
According to the Beast Wars comic book, Megatron was originally going to be an Alligator. It was proposed by the computers of his starship, the Darksyde. However, he rejected it in favor of the more powerful T-Rex. Sources say it was the new body for Megatron.