Powermaster Optimus Prime

Transformers had previously visited Nebulos and bonded with its inhabitants during the creation of the Headmasters and Targetmasters, caused severe devastation to the world and the loss of two of its most noted political leaders. To ensure that the planet would never come under threat from Transformers again, Nebulan scientist Hi-Q detonated a bomb that filled the planet's atmosphere with radiation that posed no threat to indigenous Nebulan life, but which "poisoned" Nebulan fuel supplies, making it harmful to Transformers. Not long after, the Decepticons Dreadwind and Darkwing arrived on the planet looking for the absent Scorponok, and, despite warnings, consumed Nebulan fuel. Their bodies wasted and they were rendered immobile, becoming something of a tourist attraction over time.

Hi-Q's jealous ex-partner, Hi-Test, sought to discredit his former colleague, and teamed up with a Nebulan criminal named Throttle, who stole data on Hi-Q's latest fuel conversion theories, which he had dubbed the "Powermaster Process". Using the data, Hi-Test bio-mechanically engineered his and Throttle's bodies, allowing them to transform into engines and connect to Dreadwind and Darkwing, supplying them energy directly from their own bodies. As a result, Hi-Test and Throttle regularly had to eat massive quantities of food in order to meet their partners' energy requirements.

As the Decepticon Powermasters ran roughshod over the planet, the Autobot Goldbug arrived from Earth with Getaway, Joyride and Slapdash, hoping that Nebulan science could build a new body to house the mind of Optimus Prime. When the Autobots refused to leave the planet even after being warned about the poisoned fuel, Hi-Q agreed to construct Prime's new body, while the Autobots drained their energy fending off an attack by the Decepticons. Prime's mind was placed within his new body, but he immediately began to die due to the Nebulan fuel that powered it. Realising the nobility and humanity of the Autobots, Hi-Q agreed to save Prime's life by merging with him as a Powermaster, while his assistants, Rev, Hotwire and Lube bonded to Getaway, Joyride and Slapdash to save them. Dreadwind and Darkwing were defeated by the new Powermasters and exiled from Nebulos, while the Autobots left to rejoin their fellows on Earth.

The ultimate, unintended extension of the Powermaster process later became apparent when Optimus Prime began to suffer seizures and bursts of pain. During the climactic battle with Unicron, he separated from Hi-Q and sacrificed himself to destroy the Chaos-Bringer, but Hi-Q soon realised that the seizures had been the forerunner of an incrediblemetamorphosis - the complete bonding, both mental and physical, of himself and Optimus Prime into a singular being. With Prime's body destroyed, this merging finished itself solely within Hi-Q's body, accelerated to completion by his exposure to Nucleon. The singular intellect within Hi-Q's body considered itself to be Optimus Prime, and he led the Neo-Knights on a mission to the depths of Cybertron to locate the Last Autobot, who disassembled and reconfigured Hi-Q's body into a new form for Optimus Prime.