Motormaster is a minor villain in the Transformers franchise. He acts as leader of the Stunticons.
Motormaster and the other Stunticons were introduced in the two-part second season story "The Key to Vector Sigma", where they were given life by Megatron after building them from stolen cars. They had their first task in raiding a military base. Since they were not used to seeing Decepticons transform into cars, the soldiers mistook them for Autobots. Motormaster and the others were eventually defeated by their new opposite numbers, the Autobots.
Motormaster continued to lead his team in service of Megatron. In "Masquerade", he was finally given the opportunity to go head to head with Optimus Prime and prove himself "King of the Road", but their head-on collision left Optimus Prime mostly undamaged and Motormaster in need of major repairs. He and the other Stunticons were captured by the Autobots, who then impersonated them to find out Megatron's plan. The Stunticons escaped and exposed them but were still defeated.
After the events of The Transformers: The Movie, Motormaster was among the Decepticons who went into exile on Chaar. Although he supported Cyclonus, he ended up leading the other Decepticons in agreeing to help the Quintessons, before Galvatron returned and co-opted the scheme. Motormaster continued to make occasional appearances throughout the third season, last appearing in "The Return of Optimus Prime" where he was one of the first Decepticons infected with the Hate Plague and was one of the infected Transformers to arrive at Metroplex to destroy Optimus Prime until got cured by the Matrix of Leadership.
After first being seen in a vision of the future in "Second Generation", Motormaster and the Stunticons were brought online by Megatron in Issue #22, using energy siphoned from the Creation Matrix. Their first task was to ruin the Autobots' recent good publicity. They caused havoc on a motorway, then pretended to be working with the Autobot Skids, sparking a conflict with the Aerialbots and the human team RAAT.
Motormaster quickly fell out of favour with Megatron when he suggested he could beat Optimus Prime and ended up being used as target practise by the newly-arrived Predacons. (Fortunately, they shot around him rather than at him.) After a lengthy absence, he made his final appearance in Issue #41 as part of the large Decepticon army attacking the Autobots on the moon, so may have been deactivated either during that battle or the subsequent Underbase saga.
In Marvel UK's "Earthforce" storyline, Motormaster reappeared initially as part of Shockwave's Decepticon faction, helping him ambush the Dinobots, but later served Megatron before becoming part of the combined army led by Soundwave and Starscream. In the storyline's final arc, he and the other Stunticons kidnapped journalist Irwin Spoon to stop him writing a pro-Autobot article. In the chase that followed, Motormaster was finally taken out when Dead End and Drag Strip were tricked into driving into him, but bought enough time for Bombshell to implant Irwin with a cerebro shell so he instead wrote a smear piece.
The post-movie version of the character appeared among Soundwave's generals in "Space Pirates".
Robots in Disguise (2015)
Motormaster was a major antagonist in the third season of the cartoon, leading the Stunticons on Earth. He first appeared at the end of the two-part season premiere "King of the Hill", in which Heatseeker presented him with a device that could locate Transformer technology. Motormaster frequently sent the Stunticons out on scavenger missions and they slowly acquired the ability to combine into Menasor, clashing with Ultra Bee.
In the episode "Moon Breaker", Motormaster finally had a chance to challenge Optimus Prime during an attempt to gain control of a cache located on the moon. However, the Stunticons were defeated and captured after once more forming Menasor. They were sealed into stasis pods and taken back to Cybertron as prisoners.