Henry - a puppet possessed

Trying to write a ghost story about a possessed puppet who wreaks havoc in a puppetry masterclass - fun, interesting and difficult. The idea is that a director's pre-show talk goes on too long. He demonstrates things with a puppet. Things get out of control when a malevolent spirit enters the puppet. Something like that. Writing for puppets is like pushing a shopping cart with a broken wheel on a cobbled street around a maze that may not have a way out...