Chelli is the star of the Cartoon Network/Children's Television Workshop co-production, Big Bag. Chelli is a cheerful, six-year-old orange-yellow Muppet dog with sock ears, red-patch nose, and tube hair. Chelli lives and plays at the general store run by his friend Molly, and plays around with his friends Bag and Sofie.

Chelli was pen-pals with Elmo, as seen on a second season episode when Elmo came to visit.