Goob

Goobs are standard ghosts in Luigi's Mansion 3. They are the most common ghosts in the game, as well as the first ghosts to be fought in the game. They look, behave, and attack very similarly to Greenies from Luigi's Mansion: Dark Moon, as they normally act mischievous and attack by punching. Goobs have 100 HP.

Like Greenies, Goobs can also use weapons and objects to defend themselves, such as sunglasses and shields, which can be vacuumed away or pulled away with a Suction Shot. There are also Golden Goobs similar to Gold Greenies which drop more treasure, as well as another variety that drops gems when defeated. There are also smaller variants called Mini Goobs which can be easily sucked up.

At the start of the game, when Luigi enters the Grand Lobby, there are Goobs disguised as human staff. These ghosts are seen later on in their true form the next time Luigi enters the lobby, boarding up the front doors to prevent him from escaping. Goobs are encountered normally throughout the game, usually in groups of two or more.

Special Goobs with unique behaviors appear in certain boss fights.
 * Amadeus Wolfgeist summons ballet-dancing Goobs wearing tutus and Strobulb-blocking masks for the second part of his battle. These Goobs attack by spinning into Luigi and cannot be stunned until their masks are removed; once all of them are defeated, Amadeus will possess his piano and begin attacking Luigi personally.
 * Morty's boss fight involves him filming Luigi battling a Goob wearing the upper body of a monster suit. The suit enables the Goob to breathe various types of fireballs, but once it's destroyed, the ghost behaves identically to a regular Goob.
 * The first phase of DJ Phantasmagloria's boss fight has Luigi attempting to reclaim the 15F elevator button from a troupe of Goobs dressed like breakdancers, capable of attacking with various dance moves. Once the ghost carrying the button is sucked up, the rest of them disappear as Phantasmagloria reclaims the button and attacks Luigi herself; the remaining Goobs can be fought later, but they act as normal Goobs.

The end of the game reveals the Goobs were being brainwashed by King Boo's crown gem, as they and the other ghosts quickly regain their senses once the gem vanishes from Luigi's hands as they were about to attack him. Among the rest of the standard ghosts in the game, Goobs are seen working with the protagonists to rebuild the fallen hotel through a series of pictures throughout the closing credits.