Hay,does anyone remember an old Nickelodeon cartoon ?

From what I could remember, it was about two green aliens, one was short and fat and the other was tall and skinny, and they would fly around in their space ship. Each episode would have them go around to different planets and I remember in one episode when they were on a planet the tall one (who I think was the smart one) picked an apple off a tree and he terned the apple and it was 2-D and he looked surprised by it. That's all I remember but if any one knows anything about the show ( like the name) please comment.