https://images.app.goo.gl/vzJZ4S9xJNrmai4M7

Real Name: Stanley G. (sometimes shown as R.) Perlmutter, Grade Sp-4 (later E-5, then E-6)
Occupation: dog handler, GI Joe infantryman
Legal Status: citizen of the united stated with no known criminal record
Marital Status: single
Alias(es), if any: none
Group Affiliation: GI Joe, Sergeant Slaughter's Marauders, the Drug Elimination Force, the Anti-Venom Squad

Height: 5' 8"
Hair: black
Eyes: brown
Weight: 180 lbs
Other Distinguishing Characteristics: Mutt typically wears a long mustache, and he tends to growl a lot.

Story:

Mutt grew up with five dogs in his home, and demonstrated an uncanny knack for getting them to obey his commands ever since he could walk. In fact, one time a burglar broke into his home, he told them to silently creep up on and surround the perpetrator - and they did!

His ability to control dogs only grew with age, and when Mutt enlisted in the Army years later, he went in for advanced animal control training - not to mention various security and special warfare schools. Everywhere that animals could be utilized in the field, Mutt received training.

His amazing skill and dedication got him noticed, and eventually Mutt was selected to join an elite anti-terrorist unit desperately needing new staff: the GI Joe team. Coming in with his best dog, Junkyard, Mutt jumped right in to action and showed his talent in Florida.

There he was sent on a mission to investigate an address Storm Shadow had sent a package to, only to find that Cobra Commander and a large array of his new flunkies, like Zartan, were hiding out there. While Mutt and Junkyard captured a bunch of Cobras, they ultimately got away.

Mutt went on to perform admirably in subsequent missions, and even wound up being chosen to serve on Sergeant Slaughter's Marauders team. Of course, things went a bit sour for Mutt when, during another run-in with Zartan's stooges, Junkyard was cut up with a chain saw.

Wanting some payback, Mutt hitched a ride with the Battle Force 2000 when they went after the Dreadnoks, and wound up causing more than a little bit of trouble for that team. Of course, Battle Force 2000 did manage to get their hands on those rowdy bikers as a result of Mutt's antics.

Later, when visiting his uncle in Millville with Spirit, Mutt tripped over a massive Cobra operation! Right after their arrival, Cobra Commander himself led a huge invasion of the town, and the two Joes watched helpless as he took over and brainwashed the entire populace.

Leading a resistance for a time, he and Spirit caused Cobra no end of trouble, but in the end Cobra stymied the two Joes by rolling out the regular, brainwashed police and having them arrested. Though it took several years, Mutt and Spirit were ultimately cleared of all charges.

Mutt and Junkyard stuck with the team until its first deactivation in 1994, though he returned to the fold every time the Joes had a subsequent reactivation due to increasing Cobra activity. Knowing just how evil they are, Mutt wasn't about to let them win without one heck of a fight.

(Historical Divergence)

He presumably remains with the GI Joe team to this very day, training dogs for the team and regular military operatives as well. Though the first Junkyard passed away a few years ago, he's trained several of his puppies as a replacement for field work.

Mutt even gave one the same name as his parent, to honor the original!