Galvatron

Galvatron is the more powerful form of Megatron. He's the secondary antagonist in Transformers: The Movie, and the main antagonist in the other Transformers series. How Megatron became Galvatron is mostly due to Unicron's influence, as seen in some continuities where he appears in.

Becoming Galvatron
After Megatron was severely injured by Optimus Prime and was tossed out of Astrotrain, by Starscream, he and the other badly injured Decepticons were floating in space. They eventually came across Unicron. Because of his success in killing Optimus, Megatron was demanded by Unicron to destroy Optimus' Matrix of Leadership, which was assed down to Ultra Magnus. In return, Megatron was offered a new body and new troops to command, along with a ship for transportation. Megatron initially declined the offer as he didn't want to be a servant towards anyone. However, Megatron quickly accepted Unicron's terms after Unicron attempted to kill him. Megatron was then fully repaired with a new body and transformation, and was renamed, Galvatron. Upon acquiring his new henchmen; Scourge, the Sweeps, and Cyclonus, as well as acquiring a new ship, Galvatron departed for Cybertron to be proclaimed as the true leader of the Decepticons, and additionally, to kill Starscream. When Galvatron reached Cybertron, interrupting Starscream's coronation, Starscream asked if he was Megatron, but Galvatron replied by transforming into a cannon, and shooting a powerful energy beam into Starscream, killing him. After he killed Starscream, all the Decepticons declared him as their new leader.

Assault on the Autobots
Shortly after being declared the Decepticons' true leader, Galvatron witnessed Unicron devouring both of Cybertron's moons. Galvatron cursed Unicron for destroying Cybertron's Moons, stating that they rightfully belonged to him. Unicron responded by torturing Galvatron's mind with powerful telepathy. After being tortured, Galvatron, along with a few other Decepticons, went to Earth and attacked the Autobots. Galvatron chased the Autobots into space and attempted to destroy their ships. He managed to destroy the ship with Hot Rod, Kup, and the Dino-bots inside. To prevent the other Autobots from being destroyed by Galvatron, Ultra Magnus used the Emergency Separation. This caused 3/4th of the ship to separate from the main part of the ship. Not suspecting a thing, Galvatron destroyed the lower portion of the Ship, believing that both the Autobots and the Matrix were destroyed. But Unicron knew that the Autobots, and the Matrix, were still alive and intact, so he tortured Galvatron for failing.

Acquiring the Matrix
When Galvatron asked why he was being tortured, Unicron told him that the Autobots were hiding on the Planet of Junk. Galvatron, along with a small army of Decepticons launched an assault on the Autobots while they were repairing their ship. Ultra Magnus attempted to open the Matrix, but it wouldn't open. After being denied the Matrix, Magnus was killed by the Sweeps. Upon Magnus' death, Galvatron acquired the Matrix, and decided to use the Matrix to enslave Unicron.

Betraying Unicron
Knowing that Galvatron had betrayed him, Unicron transformed into his robot mode and decided to slowly destroy Cybertron while Galvatron witnessed the destruction. Knowing that Cybertron was about to perish, Galvatron decided to join the fight and attacked Unicron, but was grabbed and eaten. When the Autobots managed to get inside Unicron, Hot Rod got separated from the others and eventually encountered Galvatron.

Fighting Hot Rod
At first, Galvatron wanted to help the Autobots destroy Unicron, but Unicron tortured Galvatron's mind again and told him to destroy Hot Rod and then, the Matrix. Hot Rod decided to use speed and stealth to fight Galvatron, but was grabbed and nearly choked to death. Galvatron gloated to Hot Rod about how pitifully easy Autobots died; first Optimus Prime, then Ultra Magnus (,though he didn't know that Ultra Magnus was repaired and revived), and finally Hot Rod. It seemed that Galvatron was about to kill Hot Rod, but Hot Rod grabbed the Matrix, and was transformed into Rodimus Prime. He was proven to be more than a match for Galvatron and proceeded to throw Galvatron out of Unicron.

Age of Extinction
Galvatron appears as the secondary antagonist of Transformers: Age of Extinction, voiced by Frank Welker. Created by KSI using technology extracted from Megatron's severed head, he is originally intended by CEO Joshua Joyce to resemble Optimus Prime. However unknown to any of the humans, their tampering re-activated Megatron's spark within and he began to influence the humans to create and entire army of transformers so he would eventually hack them and rebuild his Decepticon army. He also learned of an ancient cybertrionian weapon called a "seed" which could cyberform an entire city on it's own which he desired to replicate into more but found himself under human control and renamed Galvatron. He is first deployed when Joshua is forced by Harold Attinger to activate him and send him against Optimus Prime and his team, though Galvatron proves highly effective he also proves uncontrollable as he smashes through cars and even speaks which Joshua claims shouldn't be possible. Galvatron was then called back once Attinger sent in Lockdown to handle Optimus. Later when the Autobots escaped with the seed Galvatron activated his army and attacked Hong Kong with the intent on retrieving the seed. However his army was destroyed by the combined efforts of the Autobots and Dinobots and once Attinger and Lockdown were killed by Optimus, Galvatron retreated into Lockdown's ship, vowing to one day return and end Optimus claiming to have been "reborn:.

Trivia

 * Galvatron is voiced by Leonard Nimoy in the Transformers: The Movie, and by Frank Welker in Transformers: Generation 1
 * Megatron in the second live-action Transformers film was originally going to be named Galvatron after his resurrection. He kept his original name, however, to avoid any confusion.
 * However, he eventually named Galvatron in fourth movie, as he eventually gained powerful body thanks to humans whom uses his spark to made an artificial transformer that called Galvatron, effectively revive/evolve him in process much like Unicron did to Megatron in other versions.
 * Most incarnations of Galvatron are white with some exceptions.