I'm filming a scene with a severed head. My actor has asked me to not sever his head, so I need to figure out a mirror trick of some kind so that below his neck, it's just all clear.

We considered doing it as a greenscreened effect, but I don't think we're up to that technical piece of wizardry yet.

I can sketch out roughly what I want to do, but I would really like some advice about this. Other actors must interact with the severed head, both above and below the neckline.

We are doing as much of it with camera tricks as we can -- extreme closeups, frame-tricks, etc., but really, unless we show at least one good shot of the head just suspended in a frame, then everyone will know we're cheap-ass bastards (which we are).

Is there a NAME for this trick or a tutorial online somewhere or anything?