The villain’s full name is Baxter Stockman in Teenage Mutant Ninja Turtles.
Baxter Stockman is a scientist and recurring enemy of the turtles. Depending on the adaptation, he works for or alongside Shredder and the Foot Clan, develops robotic machines such as the Mousers, or becomes transformed into a mutant version of himself.
The character first appeared in the original Mirage Comics and was created by Kevin Eastman and Peter Laird. His most recognizable invention is the Mouser, a small robot designed to hunt and consume rodents. The machines create problems for both the turtles and New York City.
Baxter’s role changes substantially between continuities. He is portrayed as Black in the original comics and several adaptations, while the 1987 cartoon gives him a different presentation and makes him a recurring comic villain. The surname remains Stockman across the major versions.