The box is a special area outside of the game where game components (e.g. allies or monsters) that will not be used by the current game are kept. It literally means the Arkham Horror game box. A game component in the box cannot be brought into the game unless a rule or effect specifically says so. In most cases, placing a component in the box means removing it from the game altogether.
Examples of items typically found in the box
- Unused Ancient Ones
- Unused investigators
- Allies which have been been returned to the box because of a terror level increase
- Elder Signs which have been played
- Monsters such as Mask monsters which are used only with specific Ancient Ones or game variations
- Monsters such as the Mi-Go which are returned to the box when defeated