Black Light Theatre (in Czech černé divadlo) or simply Black Theatre, is a theatrical performance style characterized by the use of black box theatre augmented by black light illusion. This form of theatre originated from Asia and can be found in many places around the world. It has become a speciality of Prague, where many theatres use it.
The effect of Black Light Theatre allows invisible performers to move visible props, turning the objects into independent participants in the theatre at the same level as the human actors. Furthermore, the appearance of objects and actors in a performance can be sudden and can occur anywhere on stage, even within a few meters of an audience member (source: Wikipedia).