My favorite example of this gag is in the Bugs Bunny cartoon “Long-Haired” hare, where Bugs Bunny gets even with an opera singer who got annoyed by Bugs’ musical instrument playing as the opera singer was practicing for the night’s big performance. The opera singer (Giovanni Jones) detroyed Bugs’ banjo and harp and then tied Bugs to a tree limb by his ears.
Later on, Bugs is backstage with Mr. Jones and he fills a water sprayer with alum. When Mr. Jones goes back out on stage he sings:
FI-GARO! FI-GARO! FIGARO! FIGARO!FIGARO!FIGARO!FIGARO![sub]FIGARO![/sub]
His head shrinks and the pitch of his voice goes up while the volume goes down. That whole cartoon has always left me laughing, especially this scene and the scene where he falls into the tuba and wiggles his legs calling for help.