In Shadow theatre actors perform (very often in mime) between a source of light and a translucent screen or scrim, and the audience experience the performance on the screen. It was popular in the 19th century and often used in burlesque and vaudeville performances for example. (A particular form of this is the so-called Shadow pantomime).
There are a number of other, closely related, performance forms, using the same technique:
For example, Shadow puppetry is an ancient form of storytelling and entertainment which uses flat articulated cut-out figures (shadow puppets), which are held between a source of light and a translucent screen or scrim.("Shadow theatre" in Wikipedia)
Another very familiar variant is the playroom activity of performing a story or show using images made by hand shadows, technically referred to as "Shadowgraphy" or "ombromanie". This too has made its appearance on stage.