Duck Dodgers - Season 1 Episode 16 -

Dodgers and the Cadet travel to Earth to pick up their dry cleaning. Dodgers gets the wrong clothes and is mistaken as a Green Lantern. He finds out that an entire league of Green Lanterns have been kidnapped by the evil Sinestro and his robot army. Later, Dodgers is recruited as an official Green Lantern, and he is sent to Sinestro's base to free the superheroes.