Please! Keep your touchy-feely rhetoric to yourself, I can't stomach it! You Coopers are a bunch of dirty, attention-grubbing thieves! All of you, THIEVES!
― Dr. M to Sly Cooper
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, where he attempted to break in and steal the Cooper fortune, believing it to be rightfully his. However, despite the use of a variety of drills and other such excavation equipment over the course of many years, he was unable to breach the vault. He grew more and more paranoid as time passed, causing him to create a fortified fortress whose security was equal to that of Fort Knox, as well as a legion of mutants to serve as guards, including some large monsters.
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, as he stopped them from opening the vault and confronted Sly who he initially mistook for his father until he realized otherwise. He demanded the Cooper cane but was rejected and a fight broke out which ended with the item being lost. The Guru and Dimitri Lousteau 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 in his biplane. 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 Dr. M talked to the latter, telling him he knows how Bentley feels: a sidekick despite being intellectually superior. Bentley admits that he is smarter than Murray and Sly, but he has something that Dr. M never had: a brotherly love with his two companions. Realizing he can never talk through to Bentley, Dr. M fought him and Murray, but was defeated. Nevertheless, he still managed to follow Sly into the vault thanks to the tracker he placed on his cane.
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 and declared the Coopers to be all the same: nothing but a family of "dirty, attention-grubbing thieves". At this time, Carmelita Fox broke her way into the vault. Seeing how Sly and Carmelita felt towards each other, Dr. M took a shot at Carmelita, only for Sly to willingly take the hit. Carmelita then incapacitated Dr. M. Minutes later, despite finally seeing the Cooper treasure with his own eyes, he refused to leave the site as he spent his life searching for it. Dr. M was then killed in the collapse of the cavern. 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. He holds his face in a constant grimace.
Dr. 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, saying he was much 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 he seemed unable to truly comprehend how that was possible when he himself and Conner had never been so close. He also displayed a lack of morals and 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 victim as "sloppy" when he called for a janitor. In the inner sanctum of the Cooper Vault, he mocked Sly's speech and tried to kill Carmelita to make Sly suffer.
Dr. M's experience with Conner Cooper led him 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. When his attempts all led to failure, his hatred, greed and paranoia drove him to insanity. Much like Clockwerk, his hatred and his obsession consumed him, and he spent decades trying to open the vault. It was ultimately his obsession and insanity that killed him when he refused to leave the Cooper Vault as it 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 tracker 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 of these mods could be released, and Dr. M could also slide across the ground to leave a trail of them, with the exception of water. 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's 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 short battle with Dr. M. She destroys the remaining legs, thus causing him to topple over.
When Dr. M took control of Kaine Island to break into the Cooper Vault, he created a number of mutants to act as security around the island.
- Dr. M is possibly a reference to the mad scientist, Doctor Moreau, from H.G. Wells' novel, The Island of Doctor Moreau. Both have island strongholds with mutants and hybrids for guards. "M" may also be a reference to both "Moreau" and "Mandrill."
- He sees Bentley as an intellectual equal, but he thinks of himself and Bentley as being "side-kicks" to the Coopers.
- Dr. M is one of the three 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 one of the six characters who are actually killed off in the series. The others are Clockwerk, Arpeggio, Neyla, LeFwee and Toothpick.
- He is also the only main villain that was killed by nature, notably by boulders inside Cooper's Cave.
- He is also one of five British characters in the series. The others are Raleigh, Arpeggio, the Black Baron and Miss Decibel.
- He resembles Dr. Gavin from Sucker Punch Productions' first game, Rocket: Robot on Wheels. One major difference, however, is that Dr. Gavin is not evil, but actually just a bystander, not appearing much in the game.
- He is fought the most times out of any boss in the series.