Muzzle was a private eye on Nebulos, but he was framed and his career ended in scandal. He realized he had a chance at giving his life a new start when he heard there was an Autobot detective who was looking for a Headmaster partner. As a result, he and Nightbeat have one of the most harmonious relationships amongst the binary-bonded. Other than Nightbeat's sharpened eye for detail, one would hardly know Muzzle's in there.
Marvel Comics continuityShortly after being made a Headmaster and joining Optimus Prime's crew on Earth, Nightbeat learned of a mysterious robot corpse which had seemingly washed up on the California shoreline. Finding a serial brand from a Decepticon prison on the body, and identifying a signature Decepticon blaster as the murder weapon, Nightbeat concluded that a lone, well-armed Decepticon was hunting down escaped Autobot prisoners. Siren returned at that moment, correcting Nightbeat's analysis by informing him the prisoners weren't escapees, but deliberately let loose as prey to be hunted down. His source? The surviving prisoner, Hosehead, and the lone, well-armed Decepticon named Thunderwing who was right on their tails. Thinking quickly, Nightbeat had Muzzle binary-bond with the dead Autobot in order to reactivate his motor functions partially. Caught off-guard by his prey supposedly coming back to life right in front of him, Thunderwing left himself wide open when Muzzle disengaged and Nightbeat blew up the Autobot's fuel core at close enough range to send Thunderwing packing into the waves to douse the flames.
Following the Transformers' victory over Unicron, the Autobots secretly followed the Decepticons to Klo. However, the Decepticons were aware of the Autobots' surprise attack, and all but five Autobots were destroyed. Snapdragon kicked a head away from Nightbeat's remains.
- Nightbeat with Muzzle (Headmaster, 1988)
- Accessories: "Muzzle" Headmaster driver, seat/helmet, "Plasma Blaster" rifle, right and left "Photon Pistols"
- Muzzle transforms into part of Nightbeat's head, with the vehicle mode's "chair" and the hood's photon pistols forming the rest. When Muzzle is connected, folding down a flip-down panel on Nightbeat's chest uncovers a spring-loaded mini-Tech-Spec-meter which gives readings for Speed, Strength and Intelligence. The tumblers are activated when Muzzle (or any other Headmaster unit) is plugged into his neck socket. Muzzle has Nightbeat's face plainly visible on his back because, as a smaller Headmaster toy, he lacks the flip-down panel that covers the face, featured on larger Headmasters.
- While Nightbeat is in vehicle mode, his roof opens, allowing Muzzle to ride inside, sitting on the chair that forms Nightbeat's helmet.
- He shares a mold with the Japanese Headmaster Junior Minerva, who also got a mail-order exclusive version in Nightbeat's colors.
- Packaging photography depicts Muzzle with blue legs instead of black.
- Other than within Nightbeat's Universe-style profile, Muzzle's existence is never acknowledged in the Marvel US material—or, indeed, that Nightbeat is even a Headmaster.
- Muzzle's character model was animated once in a television commercial that advertised 1988's Headmaster Autobots and Decepticons. While Muzzle drove Nightbeat on the surface of an unidentified planet (with Siren and Hosehead at their sides), Muzzle leapt out as Nightbeat transformed into robot mode. Of note is that Muzzle's legs are blue instead of the toy's black, like the early packaging photography, and that he transforms into all of Nightbeat's head, including the "seat" and antennas.