The "Handclapping Number" is a song performed by the Anything Muppets.
On a screen split horizontally into three sections against a limbo background, twelve Muppets clap their hands while vocalizing "clap, clap, clap" and "beep beep" as well as other improvised scat.
Roosevelt Franklin, one of The Busby Twins, Farley, and Roosevelt Franklin's Mother, are among the crowd, while unnamed AMs include a Jim Henson Fat Blue (resembling Mr. Johnson), a Jerry Nelson Hot Pink (resembling Prairie Dawn), and others.
The insert has also been featured on Play with Me Sesame as a "moving and grooving" segment, with Grover appearing with the other Muppets (using chroma key). Grover ends up not having any room as more characters gradually appear.