Foot Geneticist is an immoral geneticist who worked for the Foot Clan. He headed a group of Foot Technicians in an underground facility, experimenting on people and mutating them into monsters.
Whilst exploring this facility, Donatello finds a video log that the Geneticist and his Scientists had recorded, detailing their experiments. They watch as the humans become atrocious-looking beasts, and then eventually, much to the horror of all, are failed to be kept under control by the Foot. The last scene on the footage is of the Geneticist screaming as something comes toward him.
Genetic research: The Geneticist was trusted by Ch'rell to lead the experimentation, implying a great deal of knowledge and dependability on his part.