Mud Muppets sell mud, which in some parts of the universe is also known as ceramic art, pottery, claywork or some other amalgamation of such technical, orphic and esoteric words.
Mud Muppets also create things that may not involve mud. Sometimes they are mystically inspired to make non-muddocks art, such as oily paintings, metally works, and bananas.
Crafted with blood, sweat and tears, artsy muddocks are a byproduct of the slavery of the Mud Muppets, tiny golem-like creatures trapped in eternal and slightly soggy purgatory.
The precious mud is fired in in the burning Pits of Blagsabolaralith on the planet Rog, south of the great dust nebula and very close to a large but mostly uninteresting interstellar cabbage patch.
Mud Muppets have been known to use wormholes in the fabric of space-time to send artsy muddocks to Earth, where they are strangely revered by a select subset of the human life form.
Mud Muppets hope to be compensated for their efforts. Precious metals and small green leaves used to be accepted but now beer, bacon and zippy-zappy electronic payments are preferred.