Cooper is a boy that Uncle Grandpa tried to exclude from all the awesome things as seen in the episode Except for Cooper. He is voiced by Nobody.
Cooper was never on screen for the entirety of his episode, characters will just occasionally point or look at the camera to talk to Cooper as he's a member of the audience watching Uncle Grandpa. The only remote appearance Cooper has ever made on the show was the bite marks in the vegetables he ate, to show his presence.
In the episode it can be inferred that Cooper doesn't like to eat vegetable and finds the tastes to be disgusting, showing that he has some kind of rebellious nature and own free will, as well as being a picky eater if he didn't want to eat his vegetables. People like the Spinach also think of Cooper this way as they thought he was better than them and that they were no good in Cooper's eyes.
- Cooper is the first kid to not have an appearance on the show, although to have an episode to feature him.