They hold a benefit concert for Bart featuring this musician and a lot of other fake jazz musicians quickly mentioned in an introduction:
Krusty the Clown: Hey hey! We got more jazz superstars on the way, folks! Gooey Martin, Willie Mims, Dropjaws Turner, Sketch Friendly, Tootsie Childs, Sammy Biltmore, No Talent Jones, Anwar Benitez, Bossy Marmalade, Bad Check Mazursky, Ray-Ray Takamura, Shakey Premise, Bootsy Crouton, Richard Sakai, The Premarital Sextet, C.S.I. Miami, D.W. Jitters, The Chubb Group, Cantaloupe St. Pierre and many, many more funny names.
His instrument is not indicated or shown.