Dr. Malignus is a super villain based in New York City. He has no powers, but was able to develop technology that allows him to control other people.
2003 Series
In the 2003 series, Dr. Malignus first appears in The Unconvincing Turtle Titan. In this episode, uses robotic bugs to control the actions of various people. When Silver Sentry came to investigate, he was able to control him too. Michelangelo was able to return Silver Sentry back to normal and the two defeated Dr. Malignus.
Fast Forward
In the Teenage Mutant Ninja Turtles: Fast Forward episode Clash of the Turtle Titans Dr. Malignus can be seen in the opening story Michelangelo is telling
Back to the Sewer
In the TMNT: Back to the Sewer episode Super Power Struggle Dr. Malignus tries to steal the Green Mantle's cape. But is defeated by Raph and Mikey.