At a point before the player reaches Lavender Town, members of Team Rocket invade Pokémon Tower and attempt to steal the skulls of Cubone, in order to sell them for large amounts of cash. One Cubone, however, was protected by its mother. The Cubone escaped, but its mother was killed. As a result, the Marowak's ghost remained in the Pokémon Tower, forbidding access to the topmost floor. She would appear in a disguise, avoid all thrown Poké Balls, and scare opponents so much that they would be unwilling to attack.
Even after the Silph Scope is used on it, the Marowak ghost will continue to dodge thrown Poké Balls.
Strangely, it will even dodge thrown balls in its sleep.
This makes this Marowak the only wild Pokémon encountered after the player has access to Poké Balls that is completely impossible to catch
Despite the fact that this Marowak is a ghost, it is not treated as a Template:Type2 by the game, and thus is still affected by Normal and Template:Type2 moves.
Related articles
For more information on this Pokémon's species, see Marowak.