Four million years ago, Optimus Prime ended a Decepticon attack on the Ark by directing it towards prehistoric Earth. When both factions reawakened in 1984, Optimus Prime and the Autobots fought the Decepticons on numerous occasions until 2005. During an attack on Autobot City on Earth, Prime fell in battle against Megatron and passed the Matrix of Leadership to Ultra Magnus.
Cosmos warned Optimus about a fuel plant the Decepticons were building, so Optimus took the Dinobots in his trailer and, under the guise of having a delivery for Shockwave, invaded the construction site and defeated the Decepticons. After this victory, Optimus turned his gaze skywards, and thanked Cosmos for his contribution to the Autobot cause. The Autobot Spy in the Sky
Standing only two-and-a-quarter inches tall, Smallest Transforming Transformers Optimus Prime was the smallest fully transforming G1 Optimus toy for a while, at least until the release of his chubby super-deformed Q-Transformers versions. He features an accurate transformation sequence based on the original full-sized toy, replacing the detachable hands with actual sculpted fists, and even including a tiny version of his laser rifle. Unsurprisingly, he also has little articulation and is only capable of moving his arms and legs.
While the Transformers animated series came to an end in America in 1987 after The Rebirth, production was continued in Japan with three new, exclusive animated series spin-offs to continue the story. The first of these series, Transformers: The Headmasters, supplanted the events of The Rebirth. With the Decepticons defeated, the Autobots entered into an even closer relationship with Earth. The Autobots also began the colonization of other worlds, the first of which was the planet Athenia, where Optimus Prime was stationed. It soon became apparent, however, that the consequences of releasing the energy of the Matrix to cure the Hate Plague were more far-reaching than Optimus had anticipated. Without the energy of the Matrix to act as a balancing factor, Vector Sigma had become destabilized. The Decepticons suddenly returned to exploit this, assaulting Cybertron in order to seize control of the mega-computer. Prime took a squad of troops to aid in the battle on the planet. When the arrival of the Autobot Headmasters tipped the battle in their favor, Prime broke off from the main attack and headed down into the depths of the planet, planning on stabilizing Vector Sigma at any cost.
If Optimus ordered his troops to come to the humans’ aid, they found themselves taking part in a struggle in futility, as the entire town was near-weightless, meaning they couldn’t put the humans anywhere where they wouldn’t float away once more. Then, the Autobots heard Decepticons approaching. Helpless in their current position, the Autobots were quickly eradicated by the Decepticons.