Dill Sheppard is the effeminate son of Senator Sheppard that wants to live his own adventures. In "Haylias", Stan has similar problems with Hayley wanting to go off on her own and plots to have her and Dill get married by temporarily controlling her mind through brainwashing implanted during Project Daycare. At the wedding, things go wrong when Project Daycare was found to be defective, resulting in those brainwashed to turn into their controller's killers, forcing Stan to fight Hayley for his life. Hayley shoots and temporarily kills Stan, breaking the control. Hayley and Dill have the wedding annulled and they go their separate lives.
Dill also appears in the audience in "Phantom of the Telethon".
- Dill's mannerisms and general persona are very similar to those of Truman Capote. "Dill" is also the name of a character inspired by Capote in the bestselling novel, To Kill a Mockingbird, written by Harper Lee.
Dill is voiced by Andre Sogliuzzo.