Spirit Balls are small blue balls that first appear in Luigi's Mansion 2, from mission A-4 of the Gloomy Manor. They can make objects invisible by possessing the object or item. They can turn doors, haunted armor, or anything else that Luigi may need to open or cross to advance in the game. Boos are the ones who control Spirit Balls to try and trick Luigi to make it harder for him to accomplish things.
They have 0 HP like a Creeper. But you capture them just by using your Poltergust 5000 to suck them up. If Luigi bumps into a Spirit Ball, he only loses 5HP. To make objects or items re-appear when there are no Spirit Balls around, you need to shine the Dark Light Device (Which you obtain in the Lab) at the object where you think there is suppose to be something there, the Spirit Balls will fly out and you have to suck them up in a certain amount of time. If you don't catch all the Spirit Balls in time, they will go back into the object or item they were in and make it invisible again.
- Boos may hide in objects that Spirit Balls made invisible.
- They do not appear in the Boo canister or in the Ghost Vault.