Shedinja

Shedinja (ヌケニン Nukenin) is a /-Type Pokémon, and is the result of Ninjask's evolution from Nincada. Shedinja is not an evolutionary form like some might think, but is a byproduct of Nincada's evolution; the discarded husk. This Pokémon is said to have originated from a discarded bug shell, which came to life. Peering into the crack on its back is said to steal one's spirit. To get a Shedinja in Pokémon Ruby, Sapphire, and Emerald a person must evolve their Nincada into a Ninjask and have an extra slot open in their party. No matter how much you train Shedinja, its HP always stays at 1.

Special Abilities
Its ability Wonder Guard allows it to only get hit by a special effective move.