Funny how many of the responses have this common theme of being a low budget school, and we all chose to do Wizard of Oz/The Wiz. My goodness the technical requirements of this show were a nightmare.
We had put some 'meta' into our production already, having Jitterbugs working the scene changes, making eye contact with the audience and mugging a little (not too much, but just enough), in order to sell the audience on 'Look, we're doing a musical. And we're using performers to move the scenery'. At one point in the play, after the heroes are quivering behind the huge rock as they scout out the witches castle, and the big fight happens with the witches guards, it looked like the jitterbugs had forgotten to come on and get the rock offstage. We held the stage in a silent still picture, lights up still, rock sitting there, for about 10-15 seconds. Then the rock just 'got up' and 'walked offstage' (Jitterbug hidden underneath). Generated one of the productions biggest laugh.
The rolling under the curtain trick worked for us as well. The actress playing her did a fantastic job of 'melting' and then rolling under the curtain, but also drawing attention to the way it was done (which fit our overall production aesthetic. Or it was my first musical ever, and I didn't have the good ideas expressed above about using other actors to conceal her as she disappeared. Still, it worked. The audience loved it.
Best of luck in cobbling together a solution from the excellent ideas shared already!
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Phillip Goodchild
Theatre Arts Instructor
Etobicoke ON
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