Optimus Prime returns in Transformers: The Last Knight, which is set three years after the events of the previous film. Having been frozen in the vacuum of space, Optimus has been drifting on the far reaches of Earth's solar system for some time. However, he later crash-lands on Cybertron, its atmosphere reviving him. He then confronts the being currently in control of the planet, a powerful sorceress named Quintessa, who professes to be the maker he is searching for. Optimus is easily subdued by Quintessa, who convinces him that he destroyed Cybertron and reveals that the Earth is actually Cybertron's "ancient enemy" Unicron. Redubbing him "Nemesis Prime", Quintessa brain-washes Optimus and tasks him with retrieving her stolen staff, with which she plans to drain Earth/Unicron's life force so that Cybertron can be restored. Nemesis succeeds in retrieving the staff, but is hindered by Bumblebee, whom he engages in a fierce duel. Nemesis nearly kills Bumblebee, but when the normally mute Bumblebee suddenly speaks, urging Prime to remember who he is, the sound of his oldest friend's voice is enough for Optimus to return. However, Megatron, revealed to be in league with Quintessa, swoops in and steals the staff from Optimus. Prime is then attacked and sentenced to death by the Guardian Knights for aiding Quintessa, but he is saved by Cade Yeager, who convinces Optimus to correct his mistake. Optimus leads the Autobots in the attack on Quintessa's lair, during which he slays the Infernocons and defeats Megatron. Optimus then attacks Quintessa, distracting her long enough for Bumblebee to shoot and seemingly vaporize her. At the end of the film, Optimus and the other Autobots return to Cybertron, unaware that Quintessa is actually still alive.
Of course, while Bumblebee does a lot of serious action in the films, tumbling and punching and kicking, you don’t see McFly doing a whole lot of that in the Back to the Future films. In fact, McFly doesn’t get up to too much more hard-core physical action, aside from some skateboarding and wailing on the guitar. Nevertheless, Fox does have a distinctly bowlegged gait, and you can see some of that in Bumblebee, and you can maybe see some Fox mannerisms in his more casual interactions with Sam Witwicky.
In "Reunification", Optimus is seen building his new ultimate weapon, Omega Doom. He learns that Megatron has supposedly been killed by watching a broadcast from the Autobot reporter Rook. When Kup leads the Autobots Camshaft, Hound, and Warpath, in an attempt to assassinate Optimus Prime, the Autobot leader easily defeats the four rebels. Alpha Trion then attempts to kill Optimus, but Optimus uses Omega Doom against the ancient robot. Prime then sends Doom against the Decepticons.
Prime's trailer unfolds via a spring-loaded transformation mechanism in a battle station that is positively bristling with varied weaponry. In addition to the disc launcher, it is armed with a "ripple-fire" missile launcher that fires five missiles, an air-powered rocket launcher like the one previously seen on Hero Optimus Prime, and a small laser cannon that mounts on the base's main tower. Both the missile launcher and laser cannon can disconnect and be held by Prime; his LED-fist will illuminate the laser cannon like it does his sword. Additional missiles and a second rocket are stored in grooves inside the sides of the trailer.
As part of the merchandising wave for the first Transformers film in 2007, Hasbro's Playskool line released a Transformers-themed version of Mr. Potato Head based on Optimus Prime. To keep with the potato theme, the toy was labeled "Optimash Prime" and the packaging included the slogan "More than meets the fry", a potato-oriented version of the Transformers slogan "More than meets the eye".
"But," we wondered, "How do you listen to music if you're constantly throwing this little robot?" The answer is wireless Bluetooth headphones. Here's a thought: When the music-listening technology that comes with today's yo-yos is cooler and more advanced than the music-listening technology that came with portable CD players in our day, the youth of today officially rescinds its right to ever complain about anything. Ever.
As Megatron explained that the Matrix was giving them a vision of the future, they witnessed themselves battling on Sherman Dam. The nature of their surroundings established, Megatron resumed the scheduled beating, but a series of setting shifts ended with Optimus reunited with Grimlock. Grimlock handed Prime a sword and suggested he finish Megatron for good. The War Within #5 Optimus found Megatron again, engaging him in combat and announcing that he was playing the game by Megatron's rules now—without mercy. Though he did not slay Megatron, he inflicted enough damage onto him to expunge from his memory the visions the Matrix had granted him. A short time later, Optimus joined the other Autobots in attacking the Decepticons who were trying to use Cybertron's planetary engines. Grimlock was finally impressed with Prime. Thanks to the combined efforts of Optimus and Grimlock's squad, the Decepticons were driven away and the engines were destroyed before they could tear the planet apart. Afterwards, Optimus's group arrived back at Iacon to find it destroyed. Optimus announced the Autobots were no longer evacuating the planet and threw away the Golden Disk full of the knowledge of his predecessors which the council had given him, saying he would choose his own course. The War Within #6
As part of the Robot Replicas line, this version of Optimus is a non-transforming action figure that utilizes Revoltech-style jointing. The sculpt hews much closer to the movie CGI model than is possible with the full transforming toys, plus the universal jointing of the line allows for his forearm to be replaced with his hand-cannon... or bits from other Robot Replicas.
The second Nightwatch Optimus Prime was released as part of the "AllSpark Power" second half of the Movie line. He is similar to the UK version of Nightwatch Prime, replacing most of his red and blue with different shades of blue and black, retaining his resemblance to Diaclone Powered Convoy in most respects. However, the subdued black and copper on the first Nightwatch Prime have been replaced with gold and a very bright blue, to signify the All Spark energy affecting the Transformers. The translucent parts were also cast in purple translucent plastic instead of black translucent plastic.
When Sideswipe was accused and convicted of destroying the Nova Suspension Bridge, Optimus was infuriated that one of his own Autobots could commit such a heinous act. Optimus was tasked to hunt down and deactivate Sideswipe, though the task proved to be easy as Sideswipe did not run, hide or resist. After Optimus had deactivated Sideswipe, he was approached by Prowl, who pointed out that Sideswipe's actions made little sense, as he had committed the crime in broad daylight before many witnesses. Agreeing that the Decepticons might be behind the situation, Optimus allowed Prowl to take a team of Autobots to Carob Island to clear Sideswipe's name while Optimus and Jazz stayed behind to continue working on human/Autobot relations. Prowl returned with evidence that it was indeed a Decepticon-controlled clone of Sideswipe that had committed the crime. Optimus then presumably reactivated Sideswipe when his name was cleared. Deadly Paradise