4. Marowak
Up until recently, Marowak wasn’t a Ghost-type Pokémon at all. Rather, Marowak is one of the very few Pokémon that have actually died within the lore of the games, and she’s also the only one that became a full-fledged ghost, as opposed to simply a different type of Pokémon. Marowak earns her spot on this list thanks to her unforgettable debut in Pokémon Red and Blue. In the game, it’s revealed that, after Team Rocket killed this particular Marowak, Cubone took to wearing her skull. While this is only mentioned through text conversations, there’s something particularly gruesome about the whole thing. Of course, this also begs the question: what does Cubone look like without that skull mask?