Boo's Horror Castle is the third map in story mode in the game Mario Party 9. It is tough due to the fact that every time you pass a Boo painting a Boo will come out and move 3 spaces every time and if your the captain, and the Boo or Boo's catch you you'll lose half your mini stars but don't worry there are plenty to pick up. You will only be facing 1 other person and Shy Guy again don't let Shy Guy win or he will return the mini stars to Bowser and you will have to do the board map again. The 2 bosses here are Dry Bones at the fort and King Boo beyond the Bowser Gate. Completing this Board allows you to move on to Blooper Beach. This board is also available at the start through party mode.
- If a Boo is going to catch you after your turn, he'll attack you first before you get anything on that space.
- If two Boo catch you at once, the first Boo will take half of your Mini Stars, the second Boo will take half of your Mini Stars left after the first attack. The game only shows you the total amount of Mini Stars you lose.