GASTLY

Gastly are ghost Pokemon. They are generally ball-like in appearance, and they love to play pranks on unsuspecting Pokemon and Humans alike. They have powerful paralyzing attacks, and they are one of the few Pokemon capable of handling a Psychic type Pokemon. Be warned, because capturing a Gastly and controlling it are two different things. Gastly have the ability to uncapture themselves at will. It takes a strong trainer to prevent that.