Dad Man Walking is the third part of the 3rd episode in season 4 of Dexter's Laboratory, which aired on May 2, 2003. In this episode, Dad stumbles into Dexter's laboratory while sleeping. Dexter must try to get him out without waking his father up, but the task proves to be difficult.
The name is a pun on the phrase "Dead man walking", referring to a prisoner that's set to get executed.