This is an Urban Labyrinth which involves an audience starting in a conventional theatre space, but then the characters break out of the fourth wall and out into the city streets.  The audience follow in persuit walking the streets as the characters activate flash mobs in different locations.and eventually become part of a flashmob finale. So there are two audiences to this performance. The original one that starts and returns to the theatre space and the other - the public - who encounter sporadic falshmobs occuring around their city centre.  

It is not unusual for the final theatre audience to be quite a bit bigger at the end, having picked up members of the public on the journey.  Nor is it unusual for some of the original theatre audience to be on stage at the end taking the applause of the expanded audience!

Below is video of the first example called Sugat Beet Route, piloted at the Nykobing Festival, Denmark in 2011 as part of a Drums for Peace Youth Exchange.