This final battle takes place in Transformers: The Movie (1986). The plot: in the year 2005 the Decepticons have taken over Cybertron (the Transformers' metallic home planet) and the Autobots are relegated to moon bases and a base on Earth. The Autobots try to take back Cybertron whilst dealing with a gigantic asshole named Unicron who eats planets (voiced by Orson Welles in one of his final roles).
First of all, hey, it's the year 2005 now! How about that? The movie was set in the future, and now that future is the present. This is kind of like when August 29, 1997 rolled around for fans of the Terminator films! Only I want to know where the hell are our rocket-powered skateboards that the movie promised!
The Set Up
After dispatching several Autobots with surprising ease (Brawn, Prowl, Ratchet and Ironhide) the Decepticons hijack their shuttle which had been on its way to Earth to procure desperately-needed energon for the Autobots on the moon bases. They slip past the defenses of the Autobots' city on Earth in the shuttle and proceed to open up a can of whoopass on the initially unsuspecting Autobots below. Of course, their leader, Megatron, is among the Decepticons.
After an afternoon, evening, and all-night of putting the Big Hurt on the Autobots, the Decepticons finally breach the heavily-defended Autobot City and are ready to swoop in and slaughter them. But, as luck would have it, another shuttle drops in, carrying the Dinobots, several other Autobot soldiers...and Optimus Prime, the Autobot leader.
The Battle
Optimus Prime announces, before transforming into his truck mode, for what could be the final time, "Megatron must be stopped...no matter the cost." Pissed off, presumably, because up until that point in the movie the Autobots had done little but get their asses kicked, Optimus comes truckin' into Autobot city, running down any Decepticons that were foolish enough to get in his way. Before transforming back into robot mode he withstands an onslaught of enemy fire without so much as a scratch; after transforming he blasts the shit out of about a dozen Decepticons while flying through the air. Suddenly, in rare form, our benevolent Autobot leader is one badass motherfucker. After kicking ass and taking names, he encounters Megatron.
It's ON now!
After exchanging pleasantries, Megatron and Optimus Prime begin. After dodging several blasts from Megatron's bigass cannon, Optimus socks him with his bare fist into a wall, disarming him. Megatron finds some sort of laser sword (or perhaps it's not a weapon at all and some sort of welding tool) and slices painfully into Prime. Then, in one of the finer moments of the film in terms of quality of animation, Megatron flies up into the early morning sun to put the hurt on Optimus again. However, all he gets is Prime's big fist in his face. There's a bit more fisticuffs, but in the end Megatron is disarmed yet again and Prime picks up his blaster to finish him off.
After Megatron begs for mercy, Optimus delivers this powerful line: "You who are without mercy now plead for it? I thought you were made of sterner stuff!" It's a loaded line in which, strangely enough, Optimus is actually expressing a certain level of respect for Megatron as a worthy adversary. Prime was actually surprised at how sniveling he'd become in his moment of weakness. However, Megatron wasn't beaten yet. He spies a blaster under some debris and slowly makes his way over to it while begging for his life.
Hot Rod, who had stupidly refused to listen to advice from an elder Transformer, comes running into the battle to help Optimus. This is a wet behind the ears newcomer who has a few things to learn; he sees Megatron's deception and with a "Nooo you don't, Megatron!" butts in and tries to stop him. "Out of the way, Hot Rod!" Optimus exclaims, not wanting to blast Megatron to smithereens with lil' HR in the way. Megatron grabs the blaster, uses Hot Rod as a shield, and shoots Prime at point blank range. "Fall!" he yells, then yells it twice more as he blasts Prime three more times, knocking him to the ground. Megatron tosses Hot Rod away in triumph.
With the mortally wounded Optimus Prime struggling to get back on his feet, Megatron approaches him to deliver a surely fatal shot and utters this chilling line: "It's over, PRIME!" But, Optimus has just enough chutzpah left to yell "NEVER!" and deliver a two-fisted blow to Megatron's chest and send him flying over a cliff, pieces of him going this way and that. Optimus has just enough mobility left to creep to the cliff edge and see that Megatron was indeed down. Then he collapses. With Optimus dying and Megatron defeated, the battle is largely considered a stalemate among Transformers fans.
The Decepticons, upon the defeat of their leader, retreat under the tenuous leadership of the snarky second-in-command Starscream. They load up Astrotrain, the ever-loyal Soundwave scooping up Megatron, and they leave Earth. Prime dies a short time later, near-traumatizing millions of preteen boys in the movie theaters, after Dr. Perceptor announces Prime's wounds are fatal, and after Prime gives the matrix of leadership to Ultra Magnus -- a costly mistake. Magnus' glaring ineptitude as the new leader becomes apparent later. At the end of the movie, though, it is none other than Hot Rod who ultimately rises as the permanent new Autobot leader after being able to open up the Matrix and destroy Unicron, something Magnus totally failed at doing. But, when the series moves back to the small screen, "Rodimus Prime" proves to almost be as inept as Ultra Magnus had been at being leader.
Meanwhile, as the light goes out of Optimus Prime’s eyes and his body grimly turns a dark grey, the Decepticons are fumbling through space. Astrotrain announces that they have to dump some weight or they won't make it back to Cybertron. Many injured Decepticons, most of the injuries at the hand of Prime, are dumped, and, with great pleasure, Starscream tosses Megatron out, despite his yell of "I still function!" But, Megatron encountered Unicron while floating aimlessly through space, who makes him a new body and renames him Galvatron. Now he can transform into this gigantic blast cannon, which he uses to blow the fuck out of Starscream later during his coronation ceremony.
Analysis
Firstly, let's look at the advantages that both sides had. Optimus Prime dominated Megatron in strength, determination, and general badassery. Megatron, on the other hand, if you're just considering this one battle, had the edge on resourcefulness, deception (he is a Decepticon afterall) and cleverness. In cartoon epic battles of good vs. evil, isn't this usually the other way around? It seems that, in this situation, Megatron was David and Optimus was Goliath. Prime was felled by a small blaster that had happened to just be lying around. Megatron needed not brute force to get the job done, but surgical point blank shots to presumably key areas of Prime's anatomy.
And who's blaster was that anyway? Even given that it was at point blank range, it had to be a pretty powerful weapon to do to Prime what the repeated blaster attacks of Decepticons before the battle utterly failed to do. Maybe you could argue that Prime was weakened by the battle. He came into it souped up on energon (maybe since he was the leader he got a bigger share than the rest of the autobots on the moon base; hell, Prowl was dispatched by a single shot from a puny Constructicon!). Perhaps the energon somehow strengthens the durability of their metal bodies, somebody more versed in Transformer mythology might know exactly how energon works on them (I know too much can make them drunk). But anyway, maybe Prime was tapped by the end of the battle after having used too much barreling in on a blaze of glory like he did. Or maybe the Decepticons who fired at him as he drove in were almost out after battling all night and all morning. That is more plausible by real world standards -- their weapons almost out of energy, as opposed to Prime's hull being somehow harder than usual.
At any rate, it was one of the better battles in cartoon cinema history, one that Transformers fans at least hold dear in their memories. Not only was it well written, it was action-packed with superb animation; enough Japanese animators were at work on the film to consider it anime. It left nagging questions, though. Why did Prime have to die? Hasbro killed off their most popular Transformer toy and replaced him with Rodimus fucking Prime. The 1986 television season after the movie was not as good as the two seasons had been that had lead up to it. Galvatron was definitely an upgrade from Megatron, though. He was superbly voiced by the baritone Leonard Nimoy in the movie, but in the series afterwards he was a deranged high-pitched crazy fucker that you did not want to mess with. Hot Rod was a punk (living up to his name) and his alter ego Rodimus Prime was not a whole lot better. He questioned his ability as a leader many times after the movie and even tossed the Matrix at one point and reverted back to ol' HR. At least Ultra Magnus had to be blown to pieces by Galvatron to get the Matrix away from him (right before which he surprisingly uttered the word "dammit" -- omg, he cussed!).
The Autobots needed Optimus Prime back in the worst way and, after repeated pleas from fans, was brought back in 1987 in the final episodes of the series. He was resurrected by the Junkion Wreck-Gar in a miraculous, complicated and surprising manner that shocked Transformer fandom to the core.
He freakin' fixed him.
Walter says: I think it's important to note that Megatron made sure to blast Op repeatedly in the wound that he'd made earlier with what is clearly a lightsaber.
It's been pointed out to me several times that the Quintessons were also involved in ressurecting Prime in that episode, even more than Wreck-Gar.