A ghost's heart is an object in Luigi's Mansion and its Nintendo 3DS version.
Description[]
Ghost's hearts represent the HP of nearly every regular ghosts and for every Portrait Ghost. The only ghosts lacking a heart are the Mice (including Gold Mice), Bats, and Flying Fish. In a similar yet different case, Bowling Ghosts, Ceiling Surprises, and Purple Bombers each have a heart with only 0 HP.
If Luigi flashes his flashlight onto a ghost, it gets stunned, and its heart is revealed for a few seconds. If Luigi either does not begin to vacuum a ghost a few seconds after stunning it or does not vacuum it in one round, the ghost disappears, although it reappears shortly afterward. Speedy Spirits are the only exception, as they permanently disappear if Luigi either stuns it for too long or does not vacuum it in one try.
If an element protects a ghost's heart, Luigi must first use the element's weakness to expose the ghost's heart. This only applies to three ghosts: Temper Terrors, whose heart is protected by fire but can be doused with water; Flashes, whose heart is protected by ice that can be melted with fire; and Blue Blazes, whose heart is protected by water, but can disappear from releasing ice onto it.
Portrait Ghosts require more effort to catch not only from having more HP but also because they do not reveal their hearts as easily. Depending on the Portrait Ghost, Luigi either has to find a way or wait for its heart to become visible so that he can vacuum it into the Poltergust 3000.
