Gold Ghost

Gold Ghosts are enemies in Luigi's Mansion and the first ghost type Luigi encounters in the game.

Luigi's Mansion
In Luigi's Mansion, one Gold Ghost is first seen in the Foyer as a foggy cloud carrying a key, which then goes through a door into the Parlor. There, a group of them accost him, leading him to meet Professor E. Gadd. They later appear in the training mode in E. Gadd's hideout, where they chase Luigi but do not attack him, unlike the ones found in the mansion. They reappear countless times throughout the mansion, found in groups of two or more and can be hurt by any element. Three Gold Ghosts (five in the PAL Hidden Mansion) are fought as the first wave of ghosts Vincent Van Gore sends at Luigi.

Greenies, found in Luigi's Mansion: Dark Moon, and Goobs, found in Luigi's Mansion 3, are the equivalent of the Gold Ghosts.

Mario & Luigi: Superstar Saga / Mario & Luigi: Superstar Saga + Bowser's Minions
In Mario & Luigi: Superstar Saga and its remake, a Gold Ghost briefly cameos in Starbeans Cafe after the player brews the first drink where it scares Luigi, only to be sucked up by Professor E. Gadd upon entering.

Mario Power Tennis
In Mario Power Tennis, the Gold Ghost, as well as several other generic ghost species from Luigi's Mansion, appear on the Luigi's Mansion Court and in the minigame Terror Tennis. In Mario Super Sluggers Gold Ghosts appear in the unlockable stadium Luigi's Mansion. In Mario Party 8, Gold Ghosts cameo in the minigame Specter Inspector. The Gold Ghost also appears as a part of a trophy in Super Smash Bros. Brawl.

Mario Sports Mix
Gold Ghosts make an appearance in Mario Sports Mix as spectators in the sporting events.

Nintendo Land
In the Nintendo Land minigame Luigi's Ghost Mansion, the Mii attacking the other four Mii players use a Gold Ghost costume.

Luigi's Mansion (Nintendo 3DS)

 * In-game description: An orange ghost who likes to throw spinning punches.

Reference
Spukgeist Fantasma arancione