Game Boy Horror

The Game Boy Horror is a machine designed by Professor E. Gadd in Luigi's Mansion. It allows Professor E. Gadd to communicate with Luigi. It also has a map, Luigi's stats, the Painting Ghost's descriptions, and a radar for Boos. Luigi can look in the Game Boy Horror's camera screen to allow the player to see the mansion in the first person perspective. The player can also select objects and have Luigi say something about it, much like the Tattle ability in the Paper Mario series. It can also be used on mirrors to teleport back to the Foyer. (excluding the mirror in the Mirror Room)

The Game Boy Horror was designed after the old Game Boy Color even though the Game Boy Advance was already released. This was because the then-unreleased Game Boy Advance's design was wavering throughout the early conceptual development of Luigi's Mansion.

The Game Boy Horror was going to be an item in Mario & Luigi: Superstar Saga, but it was replaced with the updated Game Boy Horror SP, which can be used to get rare items in every battle and is earned after fixing every blend. Also, Prof. E. Gadd occasionally contacts the Starbeans Café using a giant two-way Game Boy Horror that is capable of warping items between the two locations.