Boo is a recurring ghost enemy in Nintendo's Mario series, famous for chasing players only when they look away. Super Mario Galaxy, released for the Wii in 2007, brought Boo into three-dimensional haunted levels such as the Ghostly Galaxy, where its teasing laugh became part of the atmosphere. Clips of the laugh later spread through gameplay videos, reaction edits, and soundboards, where creators reused it far beyond Mario content. It remains popular because it is instantly recognisable, short, and funny rather than frightening, making it an easy shorthand for a playful scare.