See how A-listers get animated in movies and TV
Seth Rogen, Monsters vs. Aliens
The Knocked Up star voiced B.O.B., a brainless, indestructible gelatinous blob. "The concept was really funny, the other actors were funny, and I had faith that as we recorded it, we would find something funny for [my character], and I think we did," he said of the cyclops, who originally had a smaller part in the film.
Credit: VALERIE MACON/AFP/Getty Images; Dreamworks