|Cartoon debut||Buster's Green Thumb|
Duncan is a living powdered sugar doughnut that used to be in Buster's Food Cabinet. He was the second-oldest food in the cabinet, after The Kernel. In "Buster's Green Thumb," Buster's mom throws him away. Since he was not a completely organic food, it is unknown if he was put in the compost bin.
- His name is a reference to Dunkin' Donuts.