Greenies are the first ghosts that Luigi comes across in Luigi's Mansion: Dark Moon. The Greenies were originally helping Professor Elvin Gadd, but when the Dark Moon shattered, they turn against him. Greenies usually appear in groups ranging from 2-5, and have 10 HP. In the ScareScraper, sometimes their HP is more than 10. There is also a Gold form that expels large amounts of treasure when captured.
Luigi's Mansion: Dark Moon
Greenies attack Luigi with a short range punch that does 20 damage, similar to Gold Ghosts, and they are able to equip themselves with various objects to fight against Luigi. They can equip themselves with sunglasses to block the Strobulb's effect, which Luigi must vacuum off with the Power Gauge built up. They can also pick up objects (example: Keys, Pumpkins) if left on the floor for a certain amount of time. They also can use a rolling pin and pan lid (or other weapons) to increase their attack range and block the Strobulb's effect. This forces Luigi to remove the equipment or find an opportunity to use the Strobulb. Luigi can also use the Dark-Light Device to reveal them if they are invisible. If used long enough, the Greenie will taunt or lift up the item on its head, allowing Luigi to stun it and capture it.
Greenies are capable of disguising themselves as mummies. Luigi gets around this by leading the mummies into a wall or torch to burn the bandages or to give him a chance to pull them off. They also change up their attacks sometimes. In the Old Clockworks, several Greenies are found creating mini-tornadoes to drag in Luigi and do damage. They also develop a paranormal shield which gives them infinite HP that can be reduced to 10 HP by waiting for the Power Gauge to build up to at least the same power level as the color of the shield, and then pressing .
At the end of the game, like all of the other ghosts, they regain sanity and become friendly again as a result of the Dark Moon's restoration.
Mario Party 10
Super Mario Maker
Three Greenies appear around the playable character when the player presses while wearing the Professor E. Gadd costume. They do not affect gameplay.
Dark Moon Quest
Ghost Container description
NTSC: They like to tinker with things they shouldn't and wield everyday objects as weapons. First, find a way to disarm them, then stun them with your flashlight when the time is right.
Luigi's Mansion: Dark Moon official website
"They may be the mildest of the spooks you'll encounter, but they can still cause quite a bit of trouble for our intrepid ghost hunter."
Names in other languages