Flip Bit

These images were a bit puzzling to me. What IS that thing biting Flip anyway?

This is from the early Flip the Frog cartoon Flying Fists, where he is preparing for a boxing match. Earlier in the scene he is “punching a bag.” I think it’s supposed to be a pear, but I’ll accept anyone else’s guesses.

He knocks the bag around him and it grows a face.

Iwerks is the only person credited but the score must be by Carl Stalling.