Roadblock (Marvin F. Hinton) is the G.I. Joe team's rhyming heavy machine gunner/gourmet chef. This combination makes him perhaps the coolest person ever.
Roadblock used the Joes' Cybertronian technology to combat Cobra's use of the same. When Cobra Commander decided to usurp Teletran 3 to gain teleportation abilities, Roadblock was part of the team that attacked, but was accidentally transported to Cybertron when gunfire damaged Teletran 3's connection. When further complications sent various Transformers through time, teams of Joes and Cobras had to return them, or else Earth would be destroyed. Roadblock was teamed with the Baroness, Beach Head and Percy and sent to 1930s Chicago. There, they rescued Optimus Prime and fought off the Stunticons. Roadblock also got a chance to impersonate Miles Davis while infiltrating a jazz club to obtain information. (Of course he's an expert trumpeter!)
Later, after returning to Cybertron, Roadblock and Lady Jaye snuck into the control room in their underwear (I'm not making this up) and Roadblock grabbed a Decepticon pistol, which he fired to cause a distraction while Lady Jaye activated the portal to allow the final team and group of Transformers to return — the Dinobots, who saved the day.
After Serpent O.R. infected his mech it punched Grimlock in the gob. Grims ripped its arm off. Don't punch Grimlock.