Mr. Hooper practices the tuba : Season 13 Episode 111

Mr. Hooper observes Bob's music lesson with Marika and has a confession for Bob - he's always wanted to play the tuba and has been secretly practicing in the garage for the last two years, though he has little to show for it. He blows a horrid note, attracting Oscar the Grouch, who asks for more. Mr. Hooper isn't discouraged and hopes to get better so he can drive Oscar mad.