From Cheese-E-Pedia
Four whatnot schoomates, singing "Speak Up, Stop Bullying".

Whatnots are Chuck E. Cheese extras introduced in the Rockstar Era, coming with a variety of blank humanoid puppet patterns, with accessories added to create any character for puppet showtapes. The set of puppets replaced most of the store bought puppets, and are similar to the Muppet patterns, and Anything Muppets on Sesame Street.

The first whatnot puppets were introduced in "Speak Up, Stop Bullying" (a.k.a. Billy & The Bully), and other examples of showtapes with Whatnots include The Stranger Things parody, "It's the 70s", and "If Every Day Was Halloween". Notable characters made with whatnot patterns include Dr. Destructenheimer, 70-7, Jingle and Jangle, a witch, and a vampire.