Ghosts in the Pokémon world
Ghosts (Japanese: ゴースト Ghost) is souls that lives in the Fuchsia City and the Pokémon Tower.
In the games
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 needed to defeat Giovanni in Celadon Citys Rocket Game Corners Rocket Hideout and get the Silph Scope, an item made by Silph Co. that does ghosts visible. After the Marowak has been defeated, several Team Rocket Grunts that is "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: being one of MissingNo.'s forms in Generation I and also that it can be battled as a normal Pokémon by the Walkthrough Walls code in Generation II.
In the anime
In the anime, a ghost of the same sort appeard 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 their souls out of their bodies after they have been felt by a light crown. Here is it showed that the ghosts can fly around and remains their shapes they had in their living form, however, with the exception that living beings not can see them. This explains the ghost at Pokémon Tower and the previous in the episode.
