Dr. Baxter Stockman is a fictional scientist who has appeared in several versions of the Teenage Mutant Ninja Turtles shows, videogames, and comics. In each version, he is depicted as the creator of the Mousers, machines meant to seek out and destroy sewer rats (not mice, in spite of their name). Nevertheless, there are several differences among his various appearances.
In Volume 4 of the comics, however, it is revealed that Donatello kept the remnants of Stockman's cyborg body and mind hidden from his brothers for years. It was discovered that Stockman had, in Volume 2, injected April with nanobots in her shoulder during an encounter. These nanobots eventually activated and began to destroy her body; they were destroyed but are suspected to have made her sterile (although whether or not she will remain sterile after their destruction has not been explored). Donatello finally destroyed the remnants of Stockman to avenge April, including his mind; however it is possible that Baxter Stockman's entity still somehow exists and is capable of manipulating electronics and devices.
The Shredder had watched this via his cameras, and offered Stockman a job. Baxter promptly accepted, and Shredder ordered him to create a "master control device" for the Mousers. Shredder, not being able to wait, used a replication device at the Technodrome to assemble twelve Mousers. He then programmed the Mousers to find and destroy Splinter, the mutant rat who was the Turtles' master. The Mousers were destroyed by the TMNT, and they found Stockman's name on the devices. The Turtles and Splinter found Baxter with April O'Neil's help, and he told them his part of the story. They then proceeded to take Stockman's van, later to become the Turtle Van.
After a failed Mouser attack and his arrest and him being committed to an asylum, Baxter (whom Shredder broke out and first built a rat catcher) helped Shredder to get the "Three Fragments of the Eye of Sarnath" and was more evil than how good natured he was during the mouser attack.
Ultimately Baxter, tired of being abused by Shredder during their numerous attempts to gather the fragments, would betray Shredder and take the "Eye of Sarnath" for himself once Shredder acquired the three segments of the powerful artifact. Shredder ultimately put Baxter in his place and regained the powerful artifact, only moments before Donatello's Sarnathometer destroyed the Eye via a massive explosion. Baxter would crawl back to Shredder's side, but the damage would be done as Shredder began conspiring to rid himself of the turncoat scientist after a failed attempt to put a shield over the World Trade Center. Shredder convinced Krang to send Baxter to Dimension X in exchange for his mutant flunkies Bebop and Rocksteady, much to Baxter's horror.
Baxter was then placed into a disintegrator by Krang so as to eliminate Baxter since Krang had no use for the bumbling scientist. But a common housefly (which was on Baxter's clothing when he was sent through to Dimension X) accidentally flew into the disintegrator, mutating Baxter into a giant fly. (This is a reference to the 1986 remake of The Fly.) Baxter the Fly fled Dimension X all by himself and vowed revenge on Shredder and the Turtles for mutating him into a human/fly creature. While still somewhat naive and bumbling, Baxter quickly developed a cold and twisted villainous side that scared even the Shredder. Baxter aided Shredder in a plot to use a newly crafted time displacement poles that would trap the Turtles a microsecond forward in time, rendering them invisible and unable to interact with the world around them. However, when the Turtles got hold of the Jiisai plant they needed to save April, Shredder sent Baxter to recapture the plant, but he mistakenly flew between the poles. With the loss of Baxter, Shredder fled. Baxter grew insane and vowed revenge against Shredder and the Turtles. A bolt of lighting would un-displace Baxter and free him from his temporal exile, leading to him becoming whole once again to wage war against Shredder and the Turtles. Shredder conned Baxter one last time into helping him and Krang power up the Technodrome, but a fight with the TMNT and an accident with a freeze ray left Stockman more vengeful and disillusioned than ever.
Later, he would appear alone in caverns deep beneath New York, where a vast alien temple was buried. Explored by Baxter and the Turtles, it was revealed that the temple was in fact a ship, capable of traversing dimensions. Baxter attempted to repair the ship and use it to travel to Dimension X, where he could finally have revenge on the Shredder by transforming him into an ordinary housefly with the help of a trans-mutation gun that Baxter also used on Michaelangelo, turning the Ninja Turtle into a pet gerbil. Luckily, Mikey's brothers managed to save the day and return their compadre to his regular reptilian state right before they escaped the ship as it took off for Dimension X. However, without a certain piece of the warp-drive, the ship dissolved, leaving Baxter once again drifting in some far off dimension. There would be no coming back from this trip however, as we last see Baxter caught in the web of a massive inter-dimensional alien spider. It is unknown how he escaped the spider.
For almost a year Baxter was exiled in the dimensional limbo living with a super-computer that he had taken in as his sidekick. Baxter and the computer escaped and captured the turtles in order to lure out the Shredder. Baxter's computer was destroyed, save for a small memory board, and he attempted to pursue Shredder back to Dimension X. However, the portal between Earth and Dimension X was shut down, and Baxter was once again trapped in limbo. He later appears (without the computer) and mentally takes control of armies of flies in a plot to get revenge on Shredder, but he is banished to his limbo again, thanks to Donatello.
In his final appearance, Baxter escaped the limbo again and with the help of his computer board takes over the Technodrome and used Krang's mutagen to turn the city into insect mutants like himself. In the end he is defeated and once again trapped.
Baxter was voiced by Pat Fraley in the show. He also had a red-haired twin brother named Barney Stockman, also a mad scientist and with the same voice, who threw fits whenever the Turtles confused him with Baxter.
In A Better Mousetrap and Attack of the Mousers, Stockman uses his Mousers to rob banks while telling the city the Mousers are to help get rid of the city's rat problem. He also works as an officer of science for the Shredder. The Turtles and April (his assistant at the time) discover this and seek Stockman out at his headquarters, the Stocktronics building. The Turtles and April finally corner Stockman, who calls his Mousers, and retreats. Hun catches the fleeing Dr. Stockman, and turns him over to the Shredder who punishes him accordingly by ordering Hun to remove his eye (his eye is removed with a drill).
Stockman later captures Raphael, with the help of "Foot Tech Ninjas" (ninjas with the ability to become invisible); he had made the special Foot Tech garb out of an old exoskeleton found by members of the Foot Clan. Hun interrogates Raphael, but allows him to escape to allow the Foot Tech Ninja to follow Raphael back to the Turtles' lair. The Turtles successfully fend of the cloaked ninjas and Stockman is again punished for his failure by the Shredder. Carried off by the Foot Tech Ninja, Hun punishes him. Stockman's left arm is removed and replaced with a robotic prosthesis and his back broken (noted by a neck brace and required usage of a motor-driven wheelchair).
Stockman is in a severely debilitated state at this point, but he still works for the Shredder hoping to gain access to an artifact (an Utrom exosuit) picked up by the Foot in Darkness on the Edge of Town. Following a surprise attack in The Shredder Strikes Back, the Shredder wants proof positive that the Turtles have perished. Stockman volunteers to perform a DNA analysis proving the Turtles' demise in exchange for access to the Utrom exosuit. The Shredder agrees, but threatens Stockman with a "final punishment" if he doesn't come back with conclusive evidence. Stockman performs a survey of the antique store, but finds no human or mutant DNA. Distraught at this finding, Stockman manufactures his own evidence and presents it to the Shredder. Convinced that the Turtles are dead, the Shredder gives Stockman access to the exosuit.
Stockman's work for the Shredder was always about personal gain and his loyalty only went as far as his personal benefit. Having been subjected to punishment by the Shredder on more than one occasion, Stockman quickly develops an animosity for the Shredder and Hun. With newfound and unfettered access to the Utrom exosuit, Stockman plans to use the suit to create something that will give him more power. This plan comes to fruition in Return to New York when Stockman implants his body into a large four-armed exosuit. He uses the surprise attack by the Turtles as an opportunity to launch his plan of revenge against the Shredder. Stockman attacks the Shredder's throne room and battles the Shredder and the Turtles. Despite being a near indomitable foe, Stockman is defeated and seemingly explodes in the night sky.
Stockman resurfaces in Secret Origins, but with only his head left intact within a robotic spider. Unlike his previous appearances, Stockman is controlled remotely by the Shredder with a robot eye implant that covers up his previous wound that shocks Baxter when he disobeys his orders or becomes arrogant. Under the Shredder's control Baxter infiltrates the TCRI building, the secret hideaway of the Utroms. He shuts down the security of the base, sabotages the oracle pods and leads the Shredder and his men to an underground path that allows them to enter the building unseen. Stockman regains control when he is freed by the Fugitoid, an ally of the Turtles, when he alters his voice to override the Shredder's commands. Now free, Stockman attacks the Shredder, whom he still holds a grudge against, and in part contributes to the Shredder's defeat. After this incident, Stockman escapes and disappears.
He is not seen again until the Turtles encounter the mutant crocodile, Leatherhead, in What a Croc! His head is now in the chest cavity of an Utrom exo-suit, protected by a glass jar. Working independently, Stockman befriends Leatherhead and helps the crocodile build a transmat device in exchange for help with his robotic body, and Turtlebot, a robot created to fight the Turtles. Stockmans Robot is completed but Stockman's ruse is revealed when Leatherhead finds out that Stockman used to work for the Shredder. Stockman's Turtlebot is destroyed, but he escapes.
By this time, Stockman no longer has the financial backing and material support of the Foot, thus he contracts out his technical expertise to the Mob in City at War. His head is now on the shoulders of an Utrom exo-suit. And the chest cavity is covered up. With the Shredder gone, a turf war develops and Stockman creates robots to get rid of the Foot and the Purple Dragons. Stockman's robots are destroyed and he survives the turf war. Stockman again disappears, but returns again, but without a body, or head. As a gift to the Shredder, who returns in Rogue in the House, Hun has Stockman's brain placed inside a tank. At this point, Stockman is just a brain connected to an eyeball and spinal column. The tank housing his brain allows him to speak , hear,and communicate with other foot techs , but it is also equipped a volume button, and electrical shocking device, which Hun and the Shredder use to torture the scientist. This form of coercion was used to get Stockman to create a group of Foot Mechs, robotic soldiers. The Foot Mechs are eventually destroyed along with the Shredder's Freighter Headquarters, and with it, Baxter Stockman sinks to the bottom of the ocean. He is eventually fished out the water and continues to work under the Shredder. Still a brain in a tank, Stockman has upgrades added to his tank, which include a modified self-propulsion system, a crude robotic arm, and a 360° hologram of his head.
Despite an enmity shared between Stockman and the Shredder and the likelihood that Stockman will turn on him, Saki keeps him around because he considers him to be useful. This attitude begins to change when Saki hires Dr. Chaplin in New Blood. Chaplin admires Stockman and looks up to him; however, due to threats by Saki about making Chaplin a permanent replacement, Stockman keeps a wary distance from Chaplin. Stockman even goes as far as sabotaging Chaplin's inventions so that Chaplin's success won't negatively affect him. Nonetheless, Chaplin considers Stockman to be a role model and eventually creates a humanoid exosuit with a holographic head for Stockman in Mission of Gravity.
Stockman's continues to sabotage various missions, but he soon becomes a contact within the Foot for Agent Bishop. A significant act of sabotage is seen when Stockman places a program that locks the controls of Saki's starship in Exodus. When the ship is finally destroyed, and believing his enemies to have perished, Stockman joins with Agent Bishop in hopes of creating a new body. For the time being, Stockman gets a new robotic body with four legs and four arms.
Despite being an expert in robotics and engineering, Bishop changes Stockman's role and has him create clone aliens controlled by remote control in Aliens Among Us. The genetic material from these aliens inadvertently leads to a mutant outbeak. Stockman, who had been promised the tools he would need to create a new human body, is told that he can't work on his new body until the outbreak is neutralized. Stockman is then sent to New York in Outbreak to contain the threat.
Despite working with EPF forces to contain the outbreak, Stockman is unsuccessful. Although Stockman is told that he can't work on his body, he divides his time between creating a new body and the outbreak. Agent Bishop warns Stockman that he shouldn't go through with the process given the outbreak he caused, nonetheless, Stockman goes through with a cerebral transfer into his new human body in Insane in the Membrane.
The new body seems fine at first, but Stockman becomes delusional as his body begins to show signs of rejection and decomposition. The deterioration of his body, but more so his mind, leads to Stockman having visions of his mother and eventually leads him to assert that April O'Neil is the cause of everything that went wrong in his life. Stockman heads on a lone mission to seek revenge on April, but due to his continued delusions, Stockman is defeated and drowns in the East River.
Agent Bishop has Stockman's body recovered and his brain placed in a new cyborg body. However, when Stockman is brought back to life, he is mortified that he wasn't left to rest in peace. Under Agent Bishop, Stockman is forced to work on a cure for the outbreak. Stockman never figures out the cure, as Leatherhead discovers the cure in "Good Genes". After the outbreak is neutralized Stockman and Bishop inadvertently destroy the Heart of Tengu, an artifact that used to control the Foot Mystics. This act sets off a chain of events leading to the return of the original Shredder.
Stockman reappears in the fifth, "Lost" season of the series, still under Bishop's employ. During his first appearance of the season, in the episode "Membership Drive", he attempts to reprogram the reactivated Nano (found during a fortuitous E.P.F. salvage operation), with disastrous results (When Nano escaped, Bishop commented that he was beginning to understand why the Shredder kept removing Stockman's body parts). Later, in the two-part season finale, he forms part of the turtles' offensive against a resurrected demon Shredder.
In, Head of State, an episode taken place in 2105, Stockman, still under Bishop's employment, created the organic Mousers to fight off aliens. When he accidentally triggered a bio-chemical reaction, Stockman was left behind by Bishop when an alien saved him. Stockman, in a form of an alien brain, returned later to exact revenge with the help of his organic Mousers. He almost killed Bishop by renovating his head with the help of his brain transplanting device. When another explosion was triggered, Bishop redeemed his previous actions to save Stockman. After this event, Stockman works at the Department of Agriculture, who has interests with his Mousers and will eventually get a new body.
Baxter Stockman appeared in 35 episodes: