Gastly's appearance consists of a dark sphere (its "head") surrounded by light purple gas. Gastly has large, white eyes and a large mouth with a small pair of fangs. This Pokèmon captures prey by enveloping them in their poisonous gas, which can seep through skin and cause fainting. They may also immobilize prey with the paralyzing move Lick. Gastly are not blatantly malicious and do not haunt beings to harm them. They're mischievous pranksters who like to goof off and startle people.