- “Remember, as soon as you see a ghost's heart, that's your chance to vacuum 'em up!”
- —Professor E. Gadd, Luigi's Mansion
Ghosts' hearts are what serve as the HP of the ghosts in Luigi's Mansion and its remake. When the player flashes Luigi's flashlight on a ghost, it gets stunned and shows its heart for some time. The player can then suck the ghost up in the Poltergust 3000 while its heart is revealed. If an element protects a ghost's heart, Luigi must first use the element's weakness to expose the heart.
Portrait ghosts are harder to catch as they do not show their hearts as easily. The player needs to find a way to make their hearts vulnerable so that they can be sucked into the Poltergust 3000.