Elemental Ghosts are spiritual entities found in the game Luigi's Mansion. There are three different kinds of Elemental Ghosts, with each representing an individual element. Their appearance respectively matches the elemental powers they use. They can damage Luigi while in full size, but need to directly touch him to do so.
During the game, Luigi can find three different Elemental Medals, which allow Luigi to use the Elemental Ghosts to his advantage. After he found an Elemental Medal, Luigi can suck up the ghosts that match the medal with the Poltergust 3000, which charges the machine's elemental capacities. He can then shoot the element he just absorbed from the Poltergust 3000 to progress through the mansion.
Fire Elemental Ghost
Fire Elemental Ghosts can usually be found near sources of heat, like fireplaces or lamps. They resemble floating flames and house the power of fire. After Luigi has the Fire Element Medal, he can shoot flames from the Poltergust 3000 after he sucked up one of these ghosts. He can use these to expose a Flash's heart and destroy a Spark. If Luigi touches one in full size, it will set him alight, causing 20 HP of damage and making him shake his cap. The only area where Luigi can come in contact with one at full size is in the Graveyard.
Ice Elemental Ghost
Ice Elemental Ghosts are spirits that represent coldness, and they can mostly be found in cold places like freezers or buckets of ice. They appear like freezing clouds of fog. When Luigi obtains the Ice Elemental Medal, he can absorb these ghosts to enable the Poltergust 3000 to shoot a beam of ice. A Blue Blaze's heart can be exposed by this element. Also, an Ice Element Ghost can be used to freeze the river in the Pipe Room. If Luigi comes in contact with one at full size, he will take damage and be frozen and take 1 HP damage per second until he gets himself free. The only room in where Luigi can be hit by one at full size is in the Tea Room when walking on the ceiling.
Water Elemental Ghost
Water Elemental Ghosts are ghosts representing the element water, and as such they can be found near wet places like fountains or sinks. They look like blue blobs of water with white eyes. After Luigi gets the Water Element Medal, he can shoot jets of water from the Poltergust 3000. However, he must first suck up one of the Water Elemental Ghosts to charge the Poltergust 3000's energy. He can use these to suck up a Temper Terror and defeat a Spark. If Luigi is touched by one at full size, it will cause Luigi to take damage and shake the water off himself. Though there's no area in the mansion where the player can come in contact with one at full size, the only way to do so is through a cheating device like an Action Replay, by using the Walk on Ceiling code.