Baxter Stockman (TMNT 1987)

Baxter Stockman was a Caucasian scientist who worked as a humble inventor. Stockman started out an honest life trying to sell his Mousers to the Ajax pest control agency. They did not like his suggestion, deeing that it would work a little too well to rid the city of rats, and thus, put the pest control agency out of business, Stockman was thrown into the street. Shredder had watched this via his cameras, he would find Stockman and offer him a job, creating a Master Control System for an army of 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. While Stockman didn't know Shredder was using the Mousers to kill the Turtles  and Splinter, Shredder still sent the  Foot  to eliminate him. The Turtles defeated the Foot and tied Stockman to a lamppost to interrogate him, and he told them his part of the story. He would be arrested and Donatello  would use Stockman's van and the equipment he found in his apartment to create the  TurtleVan  and the  Turtle Blimp.

Stockman was later committed to an insane asylum, having since gone criminally insane due to his tales of giant talking turtles. Shredder returned to bust him out and use him to help in his attempts to defeat the Turtles. Baxter, now a lot more evil-minded that he had been before his incarceration, became his sidekick and lackey, helping him to get the "Three Fragments of the Eye of Sarnath", an alien artefact that would grant the owner virtually limitless power. Stockman eventually became fed up with Shredder's abuse and tried to use the Eye of Sarnath for himself once Shredder acquired the three segments of the powerful artifact. The Eye could create things out of thin air, or transmute objects, but it had no effect on gold. Shredder would take advantage of this to get the Eye back, even though he'd still end up getting defeated by the Turtles when 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. The final full episode with Baxter as a human would be  Case of the Killer Pizzas  where he helps Shredder unleash killer monsters from Dimension X to attack the city. Despite his treacherous nature, Stockman remained under Shredder's employ, until Shredder demanded Krang  send  Bebop  and  Rocksteady  back to  Earth  (since they were trapped in  Dimension X  at the time). Since at the time the Technodrome 's dimensional portal was weakened,  Krang  could only send them back if he got a "warm body" sent in return, so Shredder threw Stockman through the portal. Seeing no use for a human scientist, Krang had him thrown into a disintegrator unit. A fly happened to follow Stockman inside, and instead of disintegrating him, it would cross mutate him with the fly, turning him into a mutant fly.

As the fly, Stockman would now plot revenge against both the Turtles and the Shredder. While Shredder would sometimes trick Baxter into helping him, with the promise of turning him human again, Stockman would always be double crossed and twice as eager to attack Shredder the next time. Stockman's schemes would always get him trapped into either Dimension X or some other parallel dimension. During his attempts to destroy his enemies, he would befriend a sentient computer named Z| Z, who would try to help out Stockman, since over time, he would start losing his scientific mind and begin acting more like a fly, being fascinated by bright lights, craving sugar, being unable to focus on complicated tasks, and not even being able to remember exactly who it was he wanted revenge on, or why. With the computer's help and guidance, he was able to return to Earth through a small rift in the fabric of space-time, and captured the Turtles in order to lure Shredder into combat. Unable to bear the thought of anyone other than him destroying the Turtles, Shredder answered Baxter's challenge, but in the battle that ensued, the computer was destroyed, leaving only a circuit board that housed its intelligence behind. Shredder fled back to Dimension X, but when Baxter attempted to pursue him, Krang shut the portal down before Baxter emerged, again stranding the fly in interdimensional space.

Baxter's next appearance, in season five's  Landlord of the Flies , was a distinctly anomalous one. Without the computer at his side or any explanation for how he escaped his interdimensional banishment, Baxter was already back on Earth when the episode began, with a new ability: his continually devolving fly-like mentality had given him the ability to communicate with other flies, and he assembled the insects into an army in a plot to get revenge on Shredder. By this time, however, the Technodrome was stranded in the polar wastes of the arctic, and the frigid air proved distinctly inhospitable to Baxter and his fly family, stopping his scheme before it even got started. Krang was intrigued by his new ability, however, and struck a deal with Baxter, promising to transform him back into a human again if he helped them. Baxter proceeded to terrorize the city with his family army, but was one again shot off into another dimension at the episode's conclusion by Donatello's portable portal generator.

In his last encounter with the Turtles and Shredder, he tried to use Insect Essences to turn all of humanity into all kinds of mutant insects including the crew at Channel 6. The computer reminded him that he had forgotten about the Turtles, and he used his insect minions to capture them, but when questioned about what, exactly, they had ever actually done to him, Baxter admitted he couldn't even remember. Eventually, the Turtles were able to overpower Baxter, and forced him to lead them back to the Technodrome so that they could steal Shredder's retro-mutagen ray that Shredder was attempting to rebuild to thwart Baxter's plans and return the mutated humans to normal. In the chaos that ensued, the computer was destroyed, and once the retro-mutagen ray had been found, Baxter snatched it up and flew off through a dimensional portal, intending to use it to return himself to normal. While the Turtles gave chase, Shredder attempted to close the portal of the group before they could re-emerge, but the Turtles beat the clock, reclaiming the ray and making it back through in time, Baxter, however, was not so lucky, and was once again lost in limbo, never to appear again.

Besides the Mousers, Stockman was also the inventor of the Knucklehead, which Shredder utilized after he got rid of Stockman. Baxter Stockman also had a twin brother named Barney, also a mad scientist and with the same voice, who threw fits whenever the Turtles confused him with Baxter and hated Baxter and the fact that he turned into a fly. Barney Stockman appeared in the episode  Raphael Knocks Em Dead . Baxter was voiced by Pat Fraley  in the show.