(Quoted From Nintendo Power)
It's surprising how Mario's scaredy-cat little brother, Luigi, keeps finding himself in the spookiest places. Ghostly Galaxy is packed with giant Boos, trap doors, and one green-suspendered knee-trembling sibling. But saving his bacon is worth the effort- once you get Luigi safely back to the Comet Observatory, he'll help you out in your quest to find more-tricky stars.
(end quote)