Which Teenage Mutant Ninja Turtles villain is a scientist who mutates into a humanoid fly?

Baxter Stockman is the Teenage Mutant Ninja Turtles villain who mutates into a humanoid fly in several adaptations.

Stockman is generally introduced as a scientist and inventor associated with the Mouser robots. Depending on the continuity, he works for or is controlled by Shredder, and his relationship with the Foot Clan differs significantly between versions.

His fly mutation is especially associated with the 1987 animated series and later adaptations. The transformation turns the human scientist into a winged mutant antagonist, creating the character commonly known as Fly Baxter Stockman.

The character’s role is not identical in every TMNT story. In the original Mirage comics, Stockman is a robotics scientist, while some animated versions give him a more comic personality and a stronger connection to Shredder. Bebop and Rocksteady are also mutant villains, but they are not Stockman’s fly identity.