Bigmouth's Gold Bait

Bigmouth's Gold Bait is the only mission of the Bigmouth Galaxy in Super Mario Galaxy. The mission's objective is to use a Gold Shell to open a Gold Treasure Box.

Layout
The player starts in the maw of a large fish planet, next to Penguru and the Gold Treasure Box. Diving into the water, the player has to spin to break a wall of Brick Blocks. At the bottom of the waterbed are five Star Chips the player has to collect to form a Sling Star that will launch them up to the water above. Alternatively, the player can Wall Jump off of the cave wall and spin to reach the water above. In this body of water lies the Gold Shell the player needs. The player needs to carry the Gold Shell back to the start, though more Boos will be placed near the start once the Gold Shell is picked up. Using the Gold Shell to break open the Gold Treasure Box will reveal Captain Toad, who claims that he has fallen into the chest and had trouble getting out. Rescuing him will reward the player with the Power Star.