Chet Simpson

Chet Simpson, or Great Uncle Chet, is Lisa's great uncle who runs an unsuccessful shrimp company.

History
He appeared when Homer tried to show Lisa that there were successful Simpsons. When Homer asked him what he does for a living Chet said that he runs an unsuccessful shrimp company.

Since he is Lisa's great uncle and inherited the Simpson Gene, he must be a brother of Grampa Simpson and apparently the youngest of Orville Simpson's children.