The Dark-Light Device is mainly used to uncover hidden or invisible objects. This can cast a rainbow-like light that can reveal enemies called Spirit Balls, which Luigi then can use the Poltergust 5000 to vacuum them up. The Dark-Light Device also helps in capturing Boos, find tracks leading to the Polterpup, and to aid in fight with certain ghosts (such as Sneakers). It can also reveal coins and even Toad Assistants in paintings Luigi first acquires the Lab of Gloomy Manor during the fourth mission A-4: Visual Tracks.
The Dark-Light Device can be used by holding the "Y" button. Be careful as if the gauge for the Dark-Light Device is used up, it will overheat and leave Luigi wide open to ghost attacks. The Dark-Light Device can be upgraded after Luigi has cleared a mission and has the necessary money.
The Dark-Light Device returns in Luigi's Mansion 3 with the same functions as the previous game. The key difference is that there is no longer a burn-out meter allowing Luigi (and Gooigi) to use the Dark-Light Device for as long as he wants.
|Luigi · Professor E. Gadd · King Boo · Mario|
|Ancient Poltergeist · Boo · Creeper · Gobber · Greenie · Gold Greenie · Hider · Poltergeist · Polterpup · Slammer · Sneaker · Strong Gobber · Strong Greenie · Strong Hider · Strong Slammer · Strong Sneaker · The Three Sisters|
|Grouchy Possessor · Harsh Possessor · Overset Possessor · Shrewd Possessor · Tough Possessor · King Boo|
|E. Gadd's Bunker · Evershade Valley · Gloomy Manor · Haunted Towers · Old Clockworks · Secret Mine · Treacherous Mansion|
|Dark Moon · Dark-Light Device · Dual Scream · Golden Bone · Key · Poltergust 5000 · Strobulb|