It is similar to in that you can summon a trapped monster to assist you, but unlike monsters trapped in the mirrors, Hanging monsters can be summoned repeatedly and will only disappear if you release it, it rebels, it dies, or you die during a plot event. Pandora's Box Hanging can be deposited into your bank account or trashed. If you have accidentally lost your Hanging, talk to the Royal Aide in the Summoning Pool, who will replace it for you for a fee.