Monster Mash / Block Party (S01E13)

Hugo, Tillie and Simon go to Monster Sitters' HQ for a dance party. Every time Simon tries to dance like his friends, though, his arms start to wiggle and get in the way. Plus, Esme and Roy are watching Tillie. Mr. Plink tells them that Tillie needs to clean up her blocks in the backyard before she can play with her new truck, but she keeps getting distracted. (HBO Max)