In Luigi's Mansion, Professor E. Gadd (derived from the interjection "Egad!" which may be exclaimed when a person has just been frightened) arms Luigi with two of his inventions: the Poltergust 3000 (a parody of the Proton pack) and the Game Boy Horror. The Poltergust 3000 is a high-powered vacuum cleaner designed for capturing ghosts (à la Ghostbusters) and to gather treasure. To capture ghosts, the player must first shine Luigi's flashlight at them and stun them. This makes them show their heart, and gives Luigi a chance to suck them up into the Poltergust 3000, steadily reducing the ghosts' hit points to zero, at which point they can be captured. The ghosts remain in the Poltergust 3000, although certain more advanced ghosts, named "Portrait Ghosts", are extracted and put back into their portraits after a process at the end of the game's four areas. When these paintings are made, they are stored in the gallery in Professor E. Gadd's laboratory.Later in the game, Luigi locates three medallions which allow him to expel fire, water, or ice from the Poltergust 3000. These elements are needed to capture certain ghosts. The Game Boy Horror is a portable device that allows Luigi to investigate items in the mansion to find out what they are, and a functionality that indicates if a Boo is in the room and how near Luigi is to it. It also contains a map of the mansion and lets Luigi contact Professor E. Gadd and vice versa. Spread throughout the mansion are dark rooms containing ghosts, and when Luigi clears a room of all its ghosts, the lights come on and a chest usually appears. These chests can either contain keys, money, or element medallions. Whenever Luigi finds a key, his Game Boy Horror automatically indicates which room it will unlock. Its design resembles that of a Game Boy Color. Once King Boo, the final boss of Luigi's Mansion, is defeated, the player is given a rating based on the amount of treasure Luigi has found. A second version of the mansion also becomes playable, called the "Hidden Mansion". Depending on the version of the game, the entire mansion may be reversed from left to right, bosses may be different, they may move faster, ghosts (including boss ghosts) may be captured faster, and there may be more ghosts.