Dr. M was the main antagonist of Sly 3: Honor Among Thieves. He was a former member of the Original Cooper Gang who later turned his back on his teammates and sought to steal the Cooper fortune from the Cooper Vault.
He was voiced by Rick May.
Dr. M was once a member of the original Cooper Gang, working alongside Conner Cooper and Jim McSweeney. Much like Bentley in the current Cooper Gang, Dr. M was the group's technical specialist. The trio was very successful and together they amassed a large fortune. Most of this wealth went into the Cooper Vault for safekeeping. After some time, Dr. M began to feel that he was nothing more than a sidekick to Conner. Angered, he left the group and eventually took up residence on Kaine Island, the location of the Cooper Vault.
When Sly Cooper and the Cooper Gang arrived on Kaine Island, they attempted to get past Dr. M's defenses to reach the vault. Unfortunately, his intellect proved too much for them, and they not only failed to open the vault, but also lost the Cooper cane. The Guru and Dimitri both tried to recover it, but Dr. M was able to retrieve it first, using a mutated sea creature. Later, when Penelope eliminated his air defenses, Dr. M took control of a giant whale-dragonfly hybrid to attack Sly. He revealed his history to Sly, and seemingly lost the cane. In reality, he had attached a tracking device to it, allowing him to track Sly's movements through the vault. Going after him, Dr. M and his men had a brief confrontation with Murray and Bentley; where they suffered defeat, though Dr. M continued to pursue Sly.Dr. M later engaged Sly in a final battle, with Sly beating him to the edge of defeat. Sly then tried to convince him that not all Coopers were bad, giving him an example on how he and Bentley's relationship worked. Dr. M was confused as Conner Cooper was "never much of a good friend". Sly then said that all Coopers were different even if they had the same bloodline; though Dr. M refused to believe this was all true. At this time, Carmelita Fox broke her way into the vault. Seeing how Sly and Carmelita were towards each other, Dr. M took a shot at Carmelita, only for Sly to willingly take the hit. Carmelita then finished off Dr. M. Later, as the Cooper Vault collapsed, Dr. M refused to leave after finally seeing the Cooper treasure with his own eyes and spending many years trying to open the vault, and thus was killed by falling stones. Unwittingly, he facilitated Sly's relationship with Carmelita, allowing him to feign amnesia.
Dr. M is a purple mandrill. He wears blue gloves and pants and a white lab coat. On his head is a plug for interfacing with his large mutants.
PersonalityDr. M holds little respect to those he deems inferior to himself. He hated working under Conner Cooper who he believed he was superior to. He does however, hold respect for those he finds equal to himself, hence his attitude towards Bentley. Even though he sees Bentley as his equal, he sees Murray as an unintelligent "caveman". Nevertheless, Dr. M is not above giving praise even to those he considers to be beneath him, as he praised Murray for being stronger than his old teammate, McSweeney ever was.
Dr. M displayed some sociopathic qualities such as being unable to sincerely form attachments to others, which could explain why he and Conner Cooper were not close friends. He acknowledged that perhaps Sly and Bentley were true friends though seemed unable to truly comprehend how that was possible when he himself and Conner had never been so close. He also displayed his lack of morals and sadistically killed one of his men over a simple mistake by poisoning him and wickedly bringing up the henchman's family before he died. He then referred to the poor victim as sloppy trash when he summoned a janitor. In the inner sanctum of the Cooper Vault, he mocked Sly's speech and tried to kill Carmelita to make Sly suffer.
His experience with Conner Cooper led Dr. M to develop a hatred of the entire Cooper Clan. He believed that all Coopers were the same "attention-grubbing thieves", and grew obsessed with obtaining the fortune within the Cooper Vault. Much like Clockwerk, his hatred and his obsession consumed him and he spent decades trying to open the Vault. It was ultimately his obsession that killed him when he refused to leave the Cooper Vault as caved in; as Bentley explained it, Dr. M had spent most of his life lusting over the Cooper fortune, and he wasn't going to lose it no matter what the cost.
Dr. M is an extremely intelligent foe, as well as a skilled manipulator. He tricked Sly into leading him through the Cooper Vault via a tracer placed on his cane and planted doubt in Bentley's mind about his friendship with Sly. Dr. M also possessed strong physical abilities, and it is implied that he performed experiments on himself to become stronger. He was easily able to grapple with Murray without showing signs of weakening. He has also survived heavy damage without any sign of injury; for example, he was repeatedly shot at by Carmelita Fox's shock pistol, hit many times by Sly's cane, and electrocuted five times.
Dr. M was skilled at creating a variety of mechanical inventions, including weapons and methods of defense for his island fortress. However, not even he was able to create a machine capable of destroying the door to the Cooper Vault. He also had a computer interface built into his skull. This device, visible on his head as resembling a giant plug, allowed him to hook up to various weaponry, as well as some of his mutants.Dr. M's final weapon, which he used during his showdown with Sly and Carmelita, was a module that attached to the top of his head. Equipped with several spider-like legs, it also had a built in propeller that allowed Dr. M to fly. Other features included a missile launcher and a generator which could produce either water, electricity, or fire as attacks. Balls of all three could be released and Dr. M could also slide across the ground to leave a trail of them. Another of his attacks involved leaping into the air and slamming down on the ground, sending out a ring of energy. When hooked up to a device in the Cooper Vault Inner Sanctum, the module allowed Dr. M to fire a powerful laser beam. After his battle with Sly, it appears Sly has broken all but two of the spider-like legs off. When Carmelita shows up and engages in a battle with Dr. M, she destroys the remaining legs, thus causing him to topple over.
- Dr. M is a parody of the mad scientist, Doctor Moreau, from H.G. Wells's novel The Island of Doctor Moreau, since both have island strongholds and have mutants and hybrids for guards. The M is likely meant to stand for both Moreau and Mandrill.
- The Whale Fly is the only known named mutant of Dr. M's.
- He sees Bentley as an equal intellectual, but he thinks of himself and Bentley as being "side-kicks" to the Coopers.
- One of the Guards in Sly Cooper: Thieves in Time is the same animal as Dr. M.
- He was voiced by Rick May, who also famously voices the Soldier in Team Fortress 2.
- Dr. M is one of the 3 characters who explicitly has a hatred or vendetta against the Cooper Clan. The two others are Clockwerk and Le Paradox. All three are also final bosses.
- Dr. M is also one of the six characters who are actually killed off in the series. The others were Clockwerk, Arpeggio, Neyla, Captain LeFwee and Toothpick.
- He is one of six British in the series. The others are Sir Raleigh, Neyla, Arpeggio, The Black Baron and Miss Decibel.
- He also resembles Dr. Gavin from Sucker Punch Productions' first game, Rocket: Robot on Wheels The only difference is that Dr. Gavin is not evil, but actually just a bystander, since he doesn't appear much. Ironically, the main villain is JoJo the Raccoon, where in this series, The raccoon is the main hero.