Megatron (Robots in Disguise)
Megatron was the leader of the Predacons and a would-be galactic conqueror. He was capable of transforming into five modes in addition to his powerful robot mode- a bat, a dragon, a car, a jet and a giant hand.
Megatron travelled to the Earth along with his second-in-command Sky-Byte, and the troops Dark Scream, Gas Skunk and Slapper. They began their search for the O-Parts, which Megatron believed would grant him ultimate power. He first appeared in Times Square where he kidnapped the scientist Dr. Onishi (who knew the locations of the O-Parts). While he was opposed by Optimus Prime and his force of Autobots, he succeeded in kidnapping the scientist.
Megatron made several attempts to destroy the Autobots and locate the rest of the O-Parts, but he lost those parts to Prime. Megatron's first real victory came when he discovered the hull of a crashed spaceship from Cybertron with six living protoforms in it. He took the protoforms to a military base and scanned several military vehicles, creating the Decepticons. The sixth and final protoform became Scourge, who was created when Megatron scanned both a black tanker truck and Optimus Prime. The new Decepticons soon easily earned Megatron's favor over the Predacons as they were more efficient and brought better results. Megatron soon replaced Sky-Byte with Scourge as his second in command. Later, his enemies became even stronger when Ultra Magnus arrived and merged with Optimus Prime to create Omega Prime, but this only made Megatron more determined to gain the ultimate power which he dreamed of.
Much later, the Autobots gained all the O-Parts, which created a map to a labyrinth in Egypt, and the key to activating Megatron's desire for power. Megatron and his forces followed the Autobots to Egypt and a fierce battle ensued. Scourge, feeling this was not worth his time, and having his own ambitions, abandoned Megatron and the Predacons, taking the Decepticons and leaving. Megatron engaged Omega Prime in battle and fought in the power chamber located by the O-Parts, causing a huge explosion in which Megatron seemingly perished. However, the power was activated, and in a matter of hours, Megatron was resurrected as Galvatron.
In addition to his original modes he gained four more- a dinosaur, a pteranodon, an elephant and a cruiser. What makes Galvatron so dangerous is the source of his powers- he drains power from others like an energy vampire, and the more power he steals, the stronger he becomes.
He first appeared on the scene to reclaim leadership of the Predacons from Scourge (who became sub-commander again), and prevent the Autobots from gaining control of Plasma (the head of Fortress Maximus). Galvatron was determined to gain control of Maximus through Scourge, who was linked with Plasma. Scourge finally succeeded in enslaving Fortress Maximus, and brought Galvatron and Sky-Byte to a demonstration, where Scourge revealed his true ambition and ordered Fortress Maximus to destroy both Galvatron and Sky-Byte. The Autobots showed up to turn the tide and attempt to defeat the Predacons. Galvatron stunned Scourge and told Sky-Byte to bring him and follow. The Autobots regained control of Fortress Maximus.
To prevent further treachery, Galvatron gathered Scourge and the other Decepticons and removed their sentience, turning them into little more than drones. He reinstated Sky-Byte as his sub-commander and ordered him to attack the Autobots' base and recapture Plasma. A fierce battle ensued with the Autobots seeming the victors until Galvatron entered the fray and brought the Predacon starship into it to engage Fortress Maximus in battle. Galvatron transformed into his hand mode and merged with his ship to fight Fortress Maximus. Maximus destroyed the ship, and seemingly slew Galvatron. But moments later, Galvatron emerged from the wreckage in his bat mode and started absorbing power from Fortress Maximus. When he was finished, all the Autobots together were no match for him, and were forced to retreat back into the Cybertron Net.
Galvatron sent the Decepticons after the Autobots and Sky-Byte followed. Galvatron used his power to flood the Cybertron Net with the magma deep beneath the surface of the Earth in an attempt to destroy all his enemies (if Sky-Byte perished as well, so be it). Ultra Magnus attempted to stop him, but he was no match for the Preadcon leader. Galvatron unleashed millions of tiny bat-shaped power siphons and sent them into the cities of Japan to draw power from humans, just as the Autobots saved themselves from his death trap and confronted him. But the siphons were finished drawing power from people and returned to Galvatron, where he absorbed the power and became even stronger and converted into the "Devilsaurer" (which he declared the ultimate combination of strength and speed).
He began to demonstrate his power, and it was all the Autobots could do to survive, as he was impervious to whatever they threw at him. He managed to imprison the Autobots in an energy net, and threatened to destroy them unless Omega Prime led him to what he considered a limitless source of power, the Earth's core. Omega Prime complied and led Galvatron to the core. Galvatron meant to show him his true power once he finished absorbing it and destroy Omega Prime. But Fortress Maximus managed to regain consciousness and channeled his power through the Cybertron Net straight to Prime. Omega Prime was able to unleash the power of the Matrix and created the gigantic Omega Fire Sword. Galvatron converted to robot mode and the two engaged in a final duel. Omega Prime defeated Galvatron, causing a huge explosion of all the power Galvatron had stolen. Galvatron was last seen banished in space along with his followers.
In Japan, Megatron was known as Gigatron, and his five modes had specific names- the Gigabat, the Gigadragon, the Gigacar, the Gigajet, and the Gigahand. Following his upgrade, he was known as Devil Gigatron, and his four new modes had specific names- the Devilsaurer, the Devilnodon, the Devilelephant and the Devilcruiser.