What is the name of this Ravenloft adventure where imprisoned PCs control NPCs in the past?

In this Ravenloft adventure, PCs suddenly find that they are now inhabiting the bodies of unknown characters at a ball held, as far as I remember, by Strahd von Zarovich at his castle.

How is this adventure called?

I remember the adventure being crudely formatted, so I’m not entirely sure it was an official one, but I’m writing anyway hoping that it was.