Foster's Home for Imaginary Friends - Season 3 Episode 1 -

Eduardo runs away from the home to prove that he's not a coward. Meanwhile, Terrence is looking for an imaginary friend to compete in the Extreme-O-Saur Battle, and he comes across Eduardo. Terrence uses him to fight against huge imaginary friends at the dumpster. Mac, Bloo, Wilt, and Coco must search for Eduardo.