Mitt Romney is getting called a lot of names these days, but none quite so un-endearing as "serial killer." That's the latest nickname for the GOP frontrunner in an ad being run by Stephen Colbert's former Super PAC, and the comedian today went mano a mano with George Stephanopoulos on ABC's This Week, emphasizing that he's not responsible for the Super PAC's shenanigans: "I am not calling anyone a serial killer," Colbert said. "That's not my super PAC." Later, he called it "my baby,” asking, “Do you know how hard it is to give away a baby? Now imagine if that baby had a whole lot of money. Imagine how much harder that would be to give away."
Asked about his chances in South Carolina, Colbert emphasized his mock campaign was in the exploratory stage. “When you’re exploring, you don’t know what you’re going to find,” Colbert said. “I’m exploring right now. I’m a one-man Lewis and Clark. And I’m just looking for my Sacajawea.” Check out the entire verbal jousting match in the gallery. (Read more Stephen Colbert stories.)