This galaxy is unlocked by giving the Hungry Luma outside of the Bedroom dome 800 Star Bits. The Hungry Luma will appear once you’ve completed Soaring on the Desert Winds in Dusty Dune Galaxy.
Collect the Star Launcher Chips
To open the Golden Chest, you’ll need to find a Golden Shell - the normal green shell just won’t do! Head into the water and swim to the wall made of breakable blocks and spin at them to break them.
Inside the next room, you’ll need to collect all five Star Chip pieces so you can spawn in a Launch Star. There are four star chips on the outskirts of the room, near the water tornados, but watch out for the Giant Eels! When you have the four from the outskirts, head over to the centre and navigate past the Jammyfish, where you’ll find the final star chip. Once you have all five, a Star Launcher will spawn on the rock where you found the fifth star chip. Use it to swim up to the higher underwater cave where the Golden Shell is located.
Grab the Golden Shell
Swim to the top of the cave and grab the Golden Shell. Make your way back down towards the beach. In the first underwater room, you’ll now find lots of Boos but don’t worry, your golden shell acts like a spotlight and will defeat them!
Open the Golden Chest
When you’re on land with the Golden Shell, head over to the Golden Chest and throw the shell at it to break it open. A Toad will pop out and give you a Power Star!