| Robert Baxter was the childhood friend of Patsy Walker, who would one day become the costumed crimefighter Hellcat. While he and Walker were still in early adolescence, Patsy's mother Dorothy began writing fictionalized romantic adventures of her daughter as a teenager in a series of comic books. At Patsy's request, Dorothy Walker based a character in the comic book on the neighbor boy Patsy admired, Robert "Buzz" Baxter. As Baxter grew to the age of the character based on him, Dorothy Walker began increasingly to dislike him, but as a popular supporting character in the Patsy Walker comic, she could not write his fictional counterpart out of the series. To the elder Walker's dismay, her daughter married Baxter shortly after the two graduated from high school. Baxter joined the U.S. Air Force and after serving a tour of duty overseas, the newlywed couple moved onto an airbase in North Carolina. Disturbed by certain incidents that occurred to him in Vietnam, Baxter was tense and irritable as they tried to adjust to married life together. When Baxter was promoted to captain, he was sent to the civilian-owned Brand Corporation to supervise the security surrounding certain projects for which the government had contracted Brand. Baxter was vexed by the presence of the mutant Beast on the premises, unaware that he was secretly newly-hired genetics researcher Henry McCoy. At one point, Baxter's wife sheltered the wounded Beast from her husband and provided an alibi for him in exchange for the Beast's promise to help her become a costumed crimefighter. Soon after the Beast fled Brand, Patsy Walker divorced Baxter. Baxter remained at Brand, eventually being promoted to colonel. |
| Walker returned to Brand some months later in the company of the Avengers to investigate the illegal activities of a private army quartered there. It was at Brand that Walker assumed the identity of Hellcat, and journeyed with the Avengers to the Squadron Supreme's dimension. Upon their return, the Avengers were captured by Brand operatives, but Walker managed to escape and threatened to use her Hellcat claws to scratch Baxter's eyes out if he did not release the Avengers. After she raked his face to show she meant business, Baxter complied. The Brand Corporation was shut down by its parent company Roxxon Oil after an official investigation revealed Brand's illicit activities. Enraged at the way he was humiliated by his ex-wife, Baxter vowed vengeance. After resigning from the Air Force, he began treatment at Roxxon's Mutagenic Department in order to acquire superhuman abilities. The treatment augmented his strength, speed and agility, and gave him certain canine-like characteristics. He dubbed himself Mad-Dog. |
