Mad Dog is a minor nightmare. He’s extremely fast, strong, tough and aggressive. He has strong claws, a bite that can penetrate metal thanks to his bionically strengthened jaw, and enhanced senses. His teeth are able to secrete vast quantities of poison (making him foam at the mouth) to which he himself is immune. Lastly, his mental state is such that establishing mental contact with him is very hard. 

History

Robert “Mad Dog” Baxter is originally from Patsy Walker Comics. The romance comics. Really. Honest.

He was the husband of romantic heroine Patsy Walker. Unfortunately, after serving in Vietnam, he became somewhat psychologically damaged and highly irritable. While he was in the process of busting his marriage, he became responsible for the security at the criminal corporation Brand. Patsy divorced him.

Several month later, Patsy became Hellcat and fought her husband at Brand, threatening to enucleate him if he did not release the Avengers. Humiliated by his own woman, Baxter volunteered for a Brand mutagenic treatment and became Mad Dog. He’s since been a merc and professional criminal, trying two or three times to kill Patsy. He has worked with Mutant Force, Professor Power, Crossfire and AIM.

Mad Dog continues to degrade psychologically, and in recent appearances he displayed animalistic tendencies as well as long, tangled hair and a long beard. He may in time become completely bestial. 

Description

Mad Dog is a big, black haired, military man with a small moustache. He is almost always seen in costume, a dull brown and black outfit with a stylized hell hound head on the chest. He does not wear a mask anymore.

Last time he was seen, he had very long hair and a long beard. 

Personality

Remember the old joke about the DI and the pitbull ? Well, Mad Dog is the worst of both worlds. He’s as savagely aggressive as the pitbull, and quite likely to bite your arm and stay there until you die ; in combat, he usually goes berserk. And he’s as nice as the DI : he loves to order peoples around, belittle them, yell on them, humiliate them and if given a chance hit them. He especially likes hurting peoples he knew or loved, such as his ex-wife.

One wonder if his more recent attack dog-like behavior might an improvement over his old personality.