Under the Stairs
Area Gloomy Manor

Under the Stairs is a small "room" in Luigi's Mansion 2. It is similar to the Secret Pocket, as it is a very small area. It can be reached by using the Dark-Light Device on the hidden door to the left in the Patio. The door on the left of the room leads to the Foyer, although it leads to behind the fish tank, allowing Luigi to collect the Star Amethyst in Gloomy Manor. It is only used to collect that and nothing more, however when first entering the room, four golden spiders will appear for Luigi to earn some money off of.