Big Boo’s Haunt is probably the first course in Mario 64 that is a bit more complicated in its layout over the previous one. In order to access this course, you will need at least 12 Power Stars in your possession. Once you do, head through either of the wooden doors in the main lobby and go down the long hallway. If everything is right, by the way, you should see a Boo in the hallway. Go through the door at the end of the hallway to arrive in a little garden area, which has a lot of Boos. All of the Boos, except for one, will have coins upon defeating them, but the one will have a cage inside it. Note that any attack will defeat a Boo, but facing them will make them disappear, so you will want to have your back turned and maybe perform a Ground Pound on them. Approach the cage once it’s released to enter the actual course.
Big Boo’s Haunt
When you are dropped into the stage, you will be in front of a large mansion. Behind you will be a smaller building, and you won’t really find much of anything else outside of the mansion. Entering the smaller building will show nothing but an enemy and an elevator, with said elevator bringing you down into the basement of the mansion. The basement of the mansion has a few hallways, but the main draw of it is the merry-go-round. If you head there right away, you will see nothing but large pictures of Boos along the wall.
Returning to the main portion of the level, outside of the main mansion, there are actually two entrances, the front one and a back one. The back entrance only lets you access a single room that contains some Boos, which is also accessible from within the mansion proper. Once you enter via the main doors, you will find yourself on the first floor of the mansion. There will be a number of doors here, with two of the rooms having holes in the floor, which will lead to the merry-go-round in the basement should you fall into them.
After clearing Go On a Ghost Hunt, stairs will appear in the main lobby of the first floor, allowing access to the second floor. There are an equal number of rooms on the second floor, with some of them having connections to various rooms on the first floor. The one room on the right side will lead to a balcony, where you can find a blue block, which contains the Vanish Cap. This will be required to get one of the stars in this course, so you won’t be able to 100% the entire course on a first visit. In the room that connects to the balcony, you can jump on the one side to reach a ledge that connects to the third floor.
The third floor of the mansion is nothing more than a room, with a Blue Coin Block, as well as a wall you can pass through with the Vanish Cap. The door on the third floor leads to a balcony near the roof, where you will confront a Big Boo. You can Long Jump to the side portions of the roof, where you can stand safely on the top of them. The main roof itself also has a flat surface you can stand on, which will be needed to reach the central structure you see when exiting to the roof area.
Boo: They are found throughout the level and are normally only visible if you’re not looking at them when they’re looking your way. If approaching them from behind, you can just normally attack to defeat them. While looking away, a Ground Pound will take them out.
Mr. Is: These giant eyeballs are in a few areas of the level and always rotating. If they spot you, they will lock onto you and shoot pink bubbles. Once they have spotted you, run in circles around them until they shrivel up and disappear.
Mad Piano: Only found in the first room on the left when entering the mansion through the main doors. At first glance, it looks like a normal piano, but it will come to life when close enough. It chases after Mario until he gets enough distance from it. You cannot harm/defeat this enemy.
Bookends: These haunted books only appear in the rooms with bookshelves. Upon getting close enough, they appear and chase after Mario. If they hit something, they will disappear. Smaller versions appear in the library and will shoot out from the shelves. Defeating one with your own attack will yield a Blue Coin.
Scuttle Bugs: Only found in the outside area of the course, these spider-like enemies will just chase after Mario if he gets close. A simple jump on them will take them out.
Chair: These possessed chairs can be found in the second room on the left side from the main entrance. Get close enough and it rises in the air, spins, then shoots straight for Mario. It will disappear after it hits something, and cannot be defeated by your attacks.
On top of the small building
On top of the roof of the mansion