An infernal puzzle box was a magical item used to protect small objects.
Their most common use was to protect contracts signed between a devil and a mortal creature. They could also be used to safeguard small items. When an item was placed inside the box, it sealed itself automatically, creating a magical seal that was impenetrable. This magical seal also gave the box immunity to all damage. The weight of the box never changed, no matter how heavy an object placed inside it was. Once sealed, the only way to open a box was to successfully solve its puzzle. Each box's puzzle was unique and could only be solved without using magical abilities or spells. If a creature failed to solve the puzzle, they were struck by a painful psychic-based attack.