Gastly

Gastly is the original Ghost/Poison type Pokémon, introduced in Generation I alongside the very first 151 Pokémon. It is the first stage in a three-part evolution line, evolving into Haunter and then Gengar, one of the most iconic and popular Ghost-type Pokémon. Gastly is known for its ethereal, gaseous body, often depicted as a spherical mass of dark purple gas with large, menacing eyes and a perpetual grin. According to Pokédex entries, Gastly is composed almost entirely of poisonous gas, capable of inducing sleep or fainting in its victims. It typically inhabits old, dilapidated buildings, cemeteries, and dark places, often playing pranks on unsuspecting humans. Its mischievous and somewhat spooky nature has made it a beloved character in the Pokémon anime, particularly through episodes featuring its evolved forms, Haunter and Gengar, and their interactions with Ash and his friends. Gastly represents the lighter, more playful side of Ghost-type Pokémon, contrasting with the truly terrifying aspects of some other spectral creatures in the Pokémon world. Its unique typing gives it interesting matchups, being vulnerable to Psychic and Ground types, but resistant to Poison, Bug, and Grass, and completely immune to Normal and Fighting attacks.