Super Mario Galaxy/Ghostly Galaxy

Ghostly Galaxy is accessible from the Kitchen observation dome. You need 20 Stars to enter.

Star 1: Luigi and the Haunted Mansion
Once you rescue Luigi, he can be found in the Garage on the Observation Platform, from where he will help you find Hidden Luigi Stars.

Star 2: A Very Spooky Sprint
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You'll be surrounded by 3 bats that ram you, so avoid it! There's no mansion, just use the pull stars and the launch star on front of the mansion.

You'll see a boo with a helmet on it, and it wants you to race in order to get a power star.

You'll be in a racing alley with lots of bones and skulls. Don't let go of a pull star or you will fall to the beginning. And don't hit a bone with meat in it or you with bump into it and it will make you slower. At the final part, it has mines in it, but don't even panic, avoiding them makes you slower. Destory 2 of the mines, but when you fall, try catching another pull star. When you get on the planet, quickly get on top of the planet to win.

Star 3: Beware of Bouldergeist
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Beware of this planet, there are too many enimes, so spin into a stone and get a Rainbow Star. Run into the 3 bats into the planets, get on front of the bridge and run into the 3 spiders, and quickly get into the bridge and destroy the chain-chomp. But then it's easy to already lose the rainbow star, so either try to kill the 3 bats near the bridge or run into the mansion.

You'll now see a frame of a weird-looking boo. It's called a Bomb Boo. With Bomb Boos, spin into one on time to swing them around to explode a breakable thing. You can also see Bowser statues, and they are breakable. You see the Bowser statue blocking the fireplace? Destroy that and there is a Launch Star.

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Star 4 (Daredevil Comet): Bouldergeist's Daredevil Run
This Star is available when a Prankster Comet is in this Galaxy.

This is a repeat of the boss fight from Star 3, except you only have one life point.

Star 5 (Purple Comet): Purple Coins in the Bone Pen
This Star is available when a Purple Comet is in this Galaxy.

You need to collect 100 out of the total 150 Purple Coins, within a one minute time limit.

There are no coins on the initial planet upon which you land, so use the Pull Stars to navigate around. You haven't got much time, so try and go along paths where there are many coins in a row.

Star 6 (Hidden): Matter Splatter Mansion
Enter Star 2. Launch off the Shroomship. Spin Attack the higher of the two rocks, and use the Launch Star to reach a new area.

Here you will need to follow a 'spotlight', collecting keys to open doors, until you reach the Star.