The Quiet Box is a magical prison that will never be empty. You have to put one person in to get out another. The prison looks like a wardrobe. The occupant will be not able to use their powers while inside and they will fall into a trance-like state. They can't feel or sense anything. The life of a stingbulb can be prolonged this way. It contained demon prince Narvagog for many centuries until the Sphinx like tricked grandpa and the others into releasing him and replacing him with Vanessa.