The Mechanic is a recurring antagonist in Marvel's Transformers comics. He is the main antagonist of Issues #26 and #28.
Nestor Forbes was a criminal with delusions of grandeur, naming himself "the Mechanic" and objecting to being referred to as a car thief, considering himself a criminal mastermind. He had served time in jail, which had left him with a phobia of the police. Nearly arrested in a trap, he fled in a nearby ambulance, unaware it was the Autobot Ratchet. He discovered cutting and freezing guns on board and appropriated them. When Ratchet transformed to robot mode, revealing his true nature, the Mechanic froze him, then followed him back to the Ark, aiming to gain more weapons. He took a spanner that allowed him to lift heavy weights and activated the Ark's defences, turning them on the approaching Autobots. He was finally tricked when Ratchet managed to reactivate Prowl, whose police car mode caused the Mechanic to panic and flee.
The Mechanic used his newly-acquired advanced weapons to start a crime spree which attracted the attention of several underworld figures, along with the police and the Autobots Blaster and Goldbug, who had been sent to retrieve the stolen weapons. The Mechanic managed to outwit his pursuers and designed a group of cars equipped with weapons reverse-engineered from Autobot technology, which he planned to sell to other criminals. He was defeated when the Autobots joined forces with the police, allowing Blaster to electro-scramble his new cars, which fired on each other. The police arrested the gangsters, plus the Mechanic's assistant, but the Mechanic himself escaped with the weapons.