Dr. Malignus is a minor villain in the Teenage Mutant Ninja Turtles 2003 Series and the arch-enemy of Silver Sentry. His first appearence was in the episode, "The Unconvincing Turtle Titan", where he used robotic bugs to mind control people. He was later defeated by The Turtle Titan (Mikey) and Silver Sentry and sent to prison.

He is also seen in the episode, "Super Power Struggle", where he attempts to steal the Green Mantle's cape.