Megatron

Megatron is a character from the Transformers franchise created by American toy company Hasbro in 1984, based on a design by Japanese toy company Takara. The original Megatron was the leader and warlord of the Decepticons, a fictional faction of sentient self-configuring modular extraterrestrial robotic lifeforms from the planet Cybertron. He serves as the main nemesis of the Autobot leader Optimus Prime. In most incarnations, after meeting his demise, usually at Optimus's hands, Megatron would be resurrected in the form of Galvatron.

Megatron is usually depicted as having risen up from being a lowly worker to become a champion in gladiatorial combat. As a gladiator, he took the name of the legendary "Megatronus"—one of the original Thirteen Primes who betrayed his comrades and became the first Decepticon—as his own, and would similarly inspire a later villainous character. He became an activist, trying to reform Cybertron's corrupt governing body and end its unfair caste system. He mentored the young Orion Pax, and together they championed the downtrodden and preached that freedom of self-determination was the right of all sentient beings. Orion Pax would later become Optimus Prime and utilize Megatron's teachings against him when he became corrupt.

Megatron could transform into three types of guns: a Walther P38 handgun, a particle-beam weapon, and a telescopic laser cannon. He has the ability to transform between his robot shape and various weapons or vehicles, but these "alternate-modes", his origins and even personality, can vary depending on which "universe" he is depicted in. This origin is considered the most consistent between the various incarnations. Further differences are listed in the respective sections below.

Idea Wiki appearances
He also appears in several Idea Wiki projects, such as House of Animals and The Legend of Epicness.

The Legend of Epicness
Megatron is the leader of the villains in The Legend of Epicness.

House of Animals
He is an enemy in House of Animals.

Transformers R
TBD

The Funtastic World of House of Animals
TBD

Moon Silvight's Transformers: New Autobots 4 Hire
TBD. However, he would have a slightly more of a supporting Villainous role compared to many of his very own other appearances in the entire franchise.

Marvel's Spider-Man: Webbed Champion
Megatron is a crossover antagonist in the continuity of Marvel's Spider-Man: Webbed Champion, first appearing in the crossover arc "Legendary Universes", voiced by Fred Tatasciore. He appears in "Part 4: Heroes in Disguise", on which he and his crew of Decepticons come in conflict with both the Predacons led by Predaking, and the Autobots as well as Spider-Man's team of Champions, whom Megatron views only as invaders.
 * Megatron returns as an antagonist in the show's second Disney+ sequel miniseries Marvel's All-Star Multiverse, voiced again by Tatasciore. His former body as Galvatron also appears in "Lost Odyssey", among other mechanical components discarded in the Sith planet of Exegol, and salvaged by Ultron.