Noun used to describe the non-food items you've been eating all day. i.e. If you haven't eaten anything all day, or in a good long while, you've eaten a nuffin muffin.
Ulysses: Hey Hank do you want to head out to the Thai Buffet place today?
Hank: Shit yeah man, all i've had today is a big ol' nuffin muffin for lunch.