When we're first introduced to Zozo, he dances and sings his way into the scene before distracting the dog to save Ollie. What's seemingly a Big-Lipped Alligator Moment makes a lot more sense upon Episode 3's revelations that he used to dance with Nina, and from his hiding spot in the thrift store he heard Ollie's bell and assumed Nina had returned, so of course he would come to greet her with a song and dance.
