The Beanstar is a powerful, sleeping, granter of wishes that plays a major part in Mario and Luigi: Superstar Saga. It can only be awakened by a pure voice, the only one presently being Princess Peach's.
Mario & Luigi: Superstar SagaEdit
During the events of Mario and Luigi: Superstar Saga, Cackletta and her minion, Fawful tried to steal the Beanstar. To get it, they stole Princess Peach's voice, which could be used to awaken the star.
Later in the game, it is learned that the voice they stole was actually the voice of Birdo, which irritated the Beanstar, causing it to break into four pieces. Mario and Luigi searched for every piece in Yoshi Theater, Chucklehuck Woods, Oho Oasis, and they get one from Harhall, the fashion designer.
Bowletta then sends the Bros. a message about bringing the completed Beanstar to them in Joke's End, and getting Princess Peach in return. To foil her plans, Mario and Luigi also bring a fake Beanstar. However, Fawful easily sees that it is fake, and he steals the real Beanstar. However, the bros. plan to get Peach back doubles as a plan to get the Beanstar back, as Luigi infiltrates Bowletta's repaired Koopa Cruiser to retrieve the Beanstar.