Spirit Ball

Spirit Balls are ghosts that appear in Luigi's Mansion: Dark Moon and Luigi's Mansion 3 that were given to Boos from King Boo's power-enhancing jeweled crown. Their appearance is based on the will-o'-the-wisp. After Luigi uses the Dark-Light Device on an invisible object to reveal its presence, Spirit Balls fly out, and Luigi must use his Poltergust 5000 or Poltergust G-00 to suck them up in order to make the object visible. If he does not suck the Spirit Balls in a certain amount of time, they go back to the object and turn it invisible again. Spirit Balls can hurt Luigi if he touches them, dealing five HP of damage.

In Luigi's Mansion: Dark Moon, in a mission in Gloomy Manor, a Boo is seen producing some Spirit Balls. Unlike other ghosts, they cannot be sent to the Vault and do not appear in the ScareScraper; invisible objects simply get revealed without needing to suck them up.

Names in other languages
Wirrlicht Sfera Spiritata