Michael C. Hall, <I>Dexter</i> Michael C. Hall, Dexter

Parenthood has not quelled the bloodthirsty beast inside Dexter Morgan, Michael C. Hall revealed at the Dexter panel at the San Diego Comic-Con.

If anything, the scourge of other serial killers is antsier than ever, thanks to sleep deprivation.

"The theory of being a father, for all of its conventions, appealed to Dexter," Hall said. "The reality... is something else entirely. He didn't appreciate how trapped it would make him feel, and how difficult it would be to exorcise his compulsions."

Get our day-by-day guide to Comic-Con 2009

Not only is Dexter the Dad as dark as ever, he also has a new tot-sized confidante with whom to share his extracurricular exploits. "He can say anything to the baby he wants — and we might see some of that," said the actor. Watch the Season 4 trailer below for a glimpse at what Hall is talking about.

Hall was joined on the Comic-Con panel by Julie Benz, his on-screen sis/off-screen wife Jennifer Carpenter, and John Lithgow, who joins the Showtime series this season as a serial slayer dubbed "The Trinity Killer." Lithgow revealed that, five episodes into Season 4, he has yet to share a scene with any of the regulars — and that is pretty much all he revealed.

"I can't tell you anything about this marvelous character, but he has many layers and colors," Lithgow said. And for the sake of the San Diego Convention Center, maybe it's best that he did keep mum.

"I could speak two sentences right now," Lithgow teased, "that would make this whole building explode."

Lithgow also joked that the Trinity Killer's first victim "is High Commander Dick Solomon," a nod to his 3rd Rock from the Sun alter ego. "I think we need to rest my zany television persona," he said.

Watch Lithgow share a few more teases here.