Megatron is one of the main antagonists from the Transformers franchise.
2007 Transformers film
After being discovered by Archibald Witwicky, Megatron's frozen body was transported to Hoover Dam to be guarded by Sector Seven, a secret government organization who studies extraterrestrial activities. Agent Reggie Simmons explained that Megatron's technology was reverse-engineered, producing the world's modern technology (e.g. space travel, satellites, lasers, etc.) Megatron's location, as well as the Allspark's were located by a group of Decepticons led by Starscream. Frenzy thawed out Megatron who escaped outside where he had a brief reunion with Starscream, claiming that Starscream failed him again when the latter tells him that the humans have the Allspark. Megatron pursued the Autobots and their allies to Mission City where he quickly disposed of Jazz and then battled Optimus Prime. He defeated Optimus and then pursued Sam Witwicky up a condemned building, offering to keep Sam as a pet if he gave him the Allspark. Sam declined, prompting Megatron to knock the boy off the roof of the building with his flail. Optimus saved Sam and battled Megatron again. Blackout, one of Megatron's loyal followers, attempted to ambush Optimus but he was killed by U.S. soldiers. Megatron is then bombarded by missiles fired from fighter jets, knocked down by Optimus, and attempted to seize the Allspark, only to have it shoved into his exposed spark chamber by Sam, killing him. Megatron's body was dumped in the Laurentian Abyss with the other deceased Decepticons.
Transformers: Revenge of the Fallen
Megatron returns for the sequel film, Transformers: Revenge of the Fallen. Megatron is revived by Scalpel and the Constructicons with an Allspark shard and now takes on the form of a Cybertronian tank, that has the ability to fly because of its wings. He then flies to the Nemesis, the Fallen's ship, and has a tense moment with Starscream whom he accused of abandoning him. He then talks to his master, the Fallen, of the Allspark's demise before discovering its knowledge passed on to Sam is the key for providing energon. While getting away from Alice, Sam, Mikaela and Leo get picked up by Grindor and get dropped into an abandoned factory where Megatron meets them. Pinning down Sam, whom he intended to torture to death after acquiring what he needed, Megatron orders Scalpel to remove energon information from Sam's brain, but Scalpel is quickly stopped by Optimus Prime. Megatron and Prime fight outside and Starscream and Grindor join in. The fight ends with Megatron impaling Prime and blasting through Prime's chest, but then is forced to escape due to Autobot reinforcements. Megatron then declares to Starscream that they reveal themselves to the humans in order to flush out Sam. He fights in the final battle in Egypt, where Optimus tears out his right arm and fires him with his own cannon, destroying half of his face. After seeing the Fallen defeated, he and Starscream retreat, vowing that it wouldn't be over.