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 bejeweled crown. Their appearance is based on either the  or the. They have powers to hide one specific object, making it invisible and intangible, though it is still visible in mirrors. After Luigi uses the Dark-Light Device on an invisible object to reveal its presence, Spirit Balls will be forced out, and Luigi must use his Poltergust 5000 or Poltergust G-00 to suck them up. The object glows purple and is unable to be interacted with until the Balls are sucked with the Poltergust.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 5 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.

Luigi's Mansion 3 introduces a magenta variant of Spirit Balls. These Spirit Balls bring whatever objects they interact with to life, such as bins and chests. Like with the blue Spirit Balls, Luigi must use the Dark-Light Device to force the Spirit Balls out and suck them into the Poltergust G-00, turning the object back to normal.