Megatron is vicious, extremely powerful, single-minded in his goals, straight-forward and brutally direct. He is all "blunt force" in contrast to penchant for deceit and trickery. On the downside, Megatron tends to become so obsessed with the object of his desires that he can ignore "secondary" matters, glaring flaws in his plans (otherwise, he likely wouldn't have melted into ice-cold arctic water after being white hot from falling through 's atmosphere, and spent ten-thousand years as a ), and even crippling injuries in pursuit of the coveted item. Trying to talk Megatron out of blindly going for his goals is useless. He will risk his world, his troops, and even his own to achieve his goals; these things do not matter to Megatron. Even the destruction of and the is a secondary concern. In Megatron's cerebral processor, all that has become important are the whims of his and, by extension, the .
While merely dislike or disregard humans, Megatron feels a violent hatred towards them and views them as only slightly above bacteria, a feeling exacerbated by spending decades as their prisoner. Even if there was no All Spark, it's not hard to imagine that Megatron would have come to this planet anyway, just to cleanse one more world of its organic infection
- Voice actor: Hugo Weaving
- Megatron eventually succeeded in tracking the All Spark to , where he rather embarrassingly crash-landed in the Arctic Circle and was frozen solid for thousands of years. In 1897, some 100 Earth-years before the arrival of the other Transformers, he was discovered by an explorer named . Captain Witwicky accidentally activated Megatron's navigation system and caused the coordinates of the All Spark to be etched onto the explorer's glasses. Megatron remained imprisoned in the Arctic, until the 1930s, when he was dug out by the United States government and moved to a secret stronghold inside . In the years that followed, many modern devices (by Earth standards) were reverse-engineered from his frozen body.In the present day, having searched the galaxy for the All Spark and being drawn to Earth, the remaining Decepticons learned of Witwicky's glasses. Through the Internet, they determined the location of both Megatron and the All Spark inside Hoover Dam. infiltrated the dam and shut down the power systems, while Starscream attacked the external powerlines, resulting in Megatron's thawing out. Once again online, the leader of the Decepticons informed the worthless insects of his true name, shouting "I am Megatron!" (to clear up all that N.B.E.-01/Ice Man nonsense), randomly killed a few of them while destroying his former prison, then transformed and flew off after the All Spark again. He met up with Starscream for the first time in thousands of years on the outside, and, never one for pleasantries, immediately demanded to know where the Cube was. Upon learning that the humans had moved the All Spark, Megatron berated Starscream for yet another failure.After Starscream and Devastator's opening attacks in , Megatron arrived, and again declared his name (he really wants people to know who he is). The Autobots were so panicked by the sight of their long lost nemesis that called for a temporary retreat. Megatron blasted away when the diminutive Autobot attempted to attack, then threw him into the air before crushing him on top of a tower with his clawed talons. Jazz vainly fought on, asking if Megatron wanted a "piece", but doing little damage to Megatron. The Decepticon leader killed the Autobot by tearing him in half, callously declaring that he wanted "two".As ran off with the All Spark, Megatron ordered the Decepticons to . Devastator attacked the armed insects, while Starscream and fought and Ratchet for the All Spark. At that moment, Optimus Prime appeared and challenged Megatron. Millennia in the ice had done nothing to lessen the animosity Megatron felt for his brother, however. Barely managing to growl out Prime's name, he transformed and flew at Prime at full speed. The Autobot leader leapt and grabbed a hold of Megatron, who slammed him into a building before flying right through a skyscraper. Both leaders landed in the middle of an intersection, but Megatron was the first to recover and leaped upon his brother, snarling that the humans were undeserving of life. Optimus Prime replied that they had the right to choose for themselves before he threw his brother off. Megatron declared that if Prime wished to defend them, he should "join them in extinction", forming his . Before he could fire, the Autobot leader drew his and fired, hitting Megatron. The Decepticon leader shrugged off this attack, spun around from the momentum and fired his cannon, throwing Optimus Prime into the side of a building.Megatron pursued the young human who had removed the All Spark from Hoover Dam, destroying everything that stood in his way. The boy ran to a dilapidated building that was the designated coordinates for a human military evacuation team, and Megatron smashed his way through, yelling that he could smell the human maggot. Starscream destroyed the helicopter intended to take the All Spark, and Megatron burst through the floor, inquiring if it was courage or fear that compelled him. Finally cornering him on a ledge, Megatron offered that if the human gave him the All Spark, the boy might live as . The Decepticon leader relished the human's defiant refusal and destroyed the ledge the human was standing upon, sending the boy tumbling to the ground.Unfortunately, the human was caught by Optimus Prime, who then tried to escape down the side of the building before Megatron tackled him and sent all three slamming into the pavement. As a nearby attempted to run, the Decepticon expressed his disgust at the insect's proximity and flicked it away. Protecting the young boy, Prime declared that their war would end here and it was now just between the two brothers. Though lusting for the All Spark, Megatron decided to indulge his brother's obvious death wish, declaring that only he was in this fight. Despite Optimus Prime's best efforts, Megatron was relentless, matching the Autobot leader with blow after devastating blow until he collapsed. Adding insult to injury, Megatron informed Prime that his defense of the "weak" was the real reason he lost.The Decepticon leader turned his attention back to the human boy, but was suddenly attacked by the human fighter jets and 's ground soldiers firing sabot rounds. Optimus took this chance, striking Megatron and knocking him down. His armor a damaged, shattered mess, Megatron ignored the punishment and focused on the human boy, growling that he would kill the boy and that the All Spark was his. As Optimus Prime ordered the boy to place the All Spark into his chest, the human instead pushed it into the now-exposed in Megatron's chest, overloading him with energy and extinguishing the Decepticon's life force. As Optimus Prime stood over Megatron's lifeless shell, watching the light flicker out of his brother's , he remarked somberly, yet remorsefully, that Megatron had left him no choice, and removed a shard of the All Spark from his brother's spark cavity.
Megatron's body was dumped into the at its deepest point, along with the remains of the other Decepticons, where the near-freezing temperatures would, hopefully, keep them dormant indefinite.
tapped into a conversation between and General , listening to Director mention that 1) a shard of the was in storage in and 2) Megatron's body lay in the Laurentian Abyss. Ravage was sent to steal the shard, and swam to the Abyss with Scalpel, Long Haul, Mixmaster, Rampage and another Constructicon. Scalpel ordered spare parts be used to repair Megatron's body with the unnamed Constructicon, who was torn apart by his larger brethren, and then struck Megatron with the shard: the Decepticon leader was reborn as a Cybertronian tank with flight capabilities. Megatron flew up to the surface, striking a submarine on his way, before journeying into space to find the Nemesis.On the ruined ship, Megatron met up with , and chastised his subordinate for leaving him to die on Earth. Starscream defended his actions by saying that he had to take care of the hatchlings, who were dying without energon, as someone had to take command in Megatron's absence. Furious, Megatron bashed Starscream into a wall containing protoform sacks, and told Starscream that even in death, there is no command but Megatron's. Megatron met up with The Fallen, who was weakened and in a life support chair. Megatron told his master he had failed and allowed the All Spark to be destroyed, but The Fallen told Megatron that the knowledge of the All Spark had instead been transferred to the human boy who killed him, . With the knowledge within Sam's mind, they could find another energon source, hidden away from The Fallen eons ago. Already eager to avenge himself, Megatron begged The Fallen for the chance to strip the flesh from Sam, but The Fallen asked for patience. Before they could act, Megatron was to kill , who was the last of the , which made him the only one that could kill the Fallen. Megatron knew that Optimus would protect the boy, and ordered him captured.Megatron sprang a trap, dispatching to take , and to him at an abandoned factory. Although Megatron would have rather killed Sam slowly and painfully, Sam had valuable information as to the energon source's location in his mind, which he had received from his own All Spark fragment. Megatron held the boy down while Scalpel performed several invasive probes of Sam's mind. Scalpel's probes confirmed The Fallen's claims, and Scalpel declared that they needed Sam's brain on the table, something Megatron had no objections to. Just as Scalpel was ready to dissect Sam's brain, Optimus and burst in to rescue the humans. Megatron attempted to attack Optimus, but was instead shot out of the factory. Optimus drove Sam to a forest, with Megatron in hot pursuit. The Autobot and Decepticon leaders transformed and battled as Sam fled. Optimus was pretty easily dominating the fight, trash talking Megatron all the while, forcing Megatron to call his Decepticons for help.Starscream and Grindor arrived to aid their commander, as Megatron told Prime that Sam could lead them to another energon source. Kicking off his and blasting him, Megatron asked Prime if one boy was worth the future of the Cybertronians. Prime replied that he'd never stop at one, then took on all three Decepticons. Surprisingly, he was winning, stabbing Megatron multiple times and knocking off Starscream's arm. As a weary Prime tore Grindor apart, Megatron him in the back and blasted him: Prime fell, mortally wounded. As Megatron moved for the boy, the rest of the Autobots arrived and provided enough cover for Bumblebee to spirit Sam away. Already injured from the battle with Prime, Megatron and Starscream were forced to retreat.With Prime dead, Megatron was quite pleased, until Starscream informed him that the boy had escaped. Furious, Megatron smacked his lieutenant with his own severed arm and ran his treads on him for a moment for losing track of a single insect, but Starscream countered that he was one of seven billion, and could be anywhere. Considering the situation, Megatron decided it was time to end their secret war, and that if they couldn't find the boy, they'd have the humans bring him to the Decepticons. Soundwave used his scanning abilities to locate the boys parents, the rejuvenated Fallen broadcast a message to deliver Sam to them across the planet. Megatron himself broadcasted the Fallen's message by rewiring the 's radio tower.He then flew to , where nineteen thousand years before, the Fallen had built a to harness the for energon. Starscream informed him that the humans had brought Prime's body with them, and Megatron surmised the boy's intentions. Commanding the rest of the Decepticons to begin their , Megatron ordered to destroy the pyramid that was built over the harvester, while he himself chased Sam for the , which would activate the harvester. Megatron almost killed Sam, but was overwhelmed by human gunfire, and flew off.Fortunately, The Fallen managed to take the Matrix and activate the harvester, but it had already been used to resurrect Optimus. Optimus combined with and destroyed the harvester, knocking Megatron off the pyramid while Prime went for The Fallen. Quickly recovering, Megatron attacked Optimus from behind, leading to a two on one match with Megatron and the Fallen battling Prime. This one went better for Optimus than the last one, as he used Megatron's own cannon to blast half his face off, and then severed the arm. Finally, Optimus used his afterburners to send Megatron hurtling through some ruins, ending his role in the battle. Megatron was so damaged he could barely call out for "Tharscweam!", but it soon mattered little as Optimus Prime killed the Fallen. Horrified at the loss of the power behind the Decepticons, Megatron acknowledged Starscream's advice that they should flee, but noted that "This isn't over."