Ghosts in the Pokémon world

Ghosts (Japanese: ゴースト Ghost) are souls that live in Lavender Town's Pokémon Tower.

In the games

The ghost as seen in Pokémon FireRed and LeafGreen.

In the games, before getting a Silph Scope, several unidentified ghosts (namely Haunter and Gastly) appear. Later, another ghost is revealed to be Marowak killed by Team Rocket. Therefore, it now haunts the Pokémon Tower.

The player eventually needs to defeat Giovanni in Celadon City's Rocket Hideout and get the Silph Scope, an item made by Silph Co. that makes ghosts visible.(Otherwise their Pokemon will be too scared to move.) After the Marowak has been defeated, several Team Rocket Grunts that are "talking" with Mr. Fuji about that they killed it must be battled. In Generation II, Mr. Fuji created Lavender Volunteer Pokémon House for the same reason as Pokémon Tower, after the tower become the Kanto Radio Tower. The ghost itself is uncatchable.

The ghost is also related to two glitches. One of them is the fact that the sprite is used as one of MissingNo.'s forms in Generation I, while the other is that it can be battled as a normal Pokémon by walking through walls in Generation II.

In the anime

In the anime, a ghost of the same sort appeared briefly in The Tower of Terror. It even has Pokédex data there, through that data simply says that it's missing data. Later, a Haunter takes Ash's and Pikachu's souls out of their bodies after they have been killed by a chandelier. Here is it shown that ghosts can fly around and remain in the form they took while living, however, with the exception that living beings cannot see them.