I'm guessing you're talking about what he said in the movie, "Expelled?"
This is from his review of the movie:
"The whole tone of the film is whiny, paranoid — pathetic really. The narrator is somebody called Ben Stein. I had not heard of him, but apparently he is well known to Americans, for it is hard to see why else he would have been chosen to front the film. He certainly can't have been chosen for his knowledge of science, nor his powers of logical reasoning, nor his box office appeal (heavens, no), and his speaking voice is an irritating, nasal drawl, innocent of charm and of consonants. I suppose that makes it a good voice for conveying the whingeing paranoia that I referred to, so maybe that was qualification enough.
Toward the end of his interview with me, Stein asked whether I could think of any circumstances whatsoever under which intelligent design might have occurred. It's the kind of challenge I relish, and I set myself the task of imagining the most plausible scenario I could. I wanted to give ID its best shot, however poor that best shot might be. I must have been feeling magnanimous that day, because I was aware that the leading advocates of Intelligent Design are very fond of protesting that they are not talking about God as the designer, but about some unnamed and unspecified intelligence, which might even be an alien from another planet. Indeed, this is the only way they differentiate themselves from fundamentalist creationists, and they do it only when they need to, in order to weasel their way around church/state separation laws. So, bending over backwards to accommodate the IDiots ("oh NOOOOO, of course we aren't talking about God, this is SCIENCE") and bending over backwards to make the best case I could for intelligent design, I constructed a science fiction scenario. Like Michael Ruse (as I surmise) I still hadn't rumbled Stein, and I was charitable enough to think he was an honestly stupid man, sincerely seeking enlightenment from a scientist. I patiently explained to him that life could conceivably have been seeded on Earth by an alien intelligence from another planet (Francis Crick and Leslie Orgel suggested something similar — semi tongue-in-cheek). The conclusion I was heading towards was that, even in the highly unlikely event that some such 'Directed Panspermia' was responsible for designing life on this planet, the alien beings would THEMSELVES have to have evolved, if not by Darwinian selection, by some equivalent 'crane' (to quote Dan Dennett).
Well, you will have guessed how Mathis/Stein handled this. I won't get the exact words right (we were forbidden to bring in recording devices on pain of a $250,000 fine, chillingly announced by some unnamed Gauleiter before the film began), but Stein said something like this. "What? Richard Dawkins BELIEVES IN INTELLIGENT DESIGN." "Richard Dawkins BELIEVES IN ALIENS FROM OUTER SPACE."
http://io9.gizmodo.com/375766/richard-dawkins-the-rap-video?mail2=true