Big Boo's Haunt

Big Boo's Haunt is a three-story mansion located in a small cage. It is the fifth course in Super Mario 64 and Super Mario 64 DS. Unlike most other courses, Big Boo's Haunt is one of the rare courses that is not accessed via a painting. Instead, Mario must travel to the castle's courtyard (after he has collected twelve Power Stars, fifteen in the DS remake) and defeat a Big Boo. The Boo will drop a small cage containing the course. Mario shrinks upon entering this cage. The level is bounded by what appears to be the bars of a cage, suggesting, along with his entrance into the level, that Mario has shrunk. The background is that of a moonlit night.

Big Boo's Haunt is inhabited by none other than Big Boo himself. There is a small shack on the side of the mansion that has a lift to the basement. In the center of the basement is a strange large merry-go-round. There is also the Mad Piano (a piano that comes to life and tries to bite Mario if he gets too close). Big Boo's Haunt is also home to Big Mr. I. There are two entrances into the main building: the front door immediately visible upon entering the level, and a single back door that leads into a room containing two Boos. This course is one of a few that contain bridges made of bricks that fall away when walked upon. It should also be noted that there is no way to fall "off the course".

Levels
The level titles and numbers correspond to Super Mario 64 unless otherwise noted.

Star 1: Go On A Ghost Hunt
This level is the same in both Super Mario 64 and its remake, Super Mario 64 DS. Mario must defeat every Boo on the first floor, and once every one of them has been defeated, Big Boo appears in the main room of the mansion. He can be defeated by being punched from behind, as he turns invisible whenever Mario faces him from the front. Once Mario has defeated him, a Star appears on the second floor and a staircase appears from the ground to reach it.

Star 2: Ride Big Boo's Merry-Go-Round
This level is the same in both Super Mario 64 and its remake. Once he enters the course, Mario should enter the shack near the mansion. He'll take the lift to the basement and hear "circus music" as he progress onward. There will be a door that leads into a room with a spinning floor and Boo paintings around the walls. One painting near a doorway will shoot out fire while Boos will appear out of one on the left side of the other doorway. After Mario defeats five normal Boos, Big Boo will appear again and give up another Star once Mario defeats him in the same way he did in the first mission.

Star 3: Secret of the Haunted Books
This level is the same in both Super Mario 64 and its remake. The third mission for the red-capped plumber is on the second floor. Once Mario reaches the second floor of the Foyer, he should take the right hand door on the left side of the room. This will lead him into a small library. As Mario heads around the library, small books shoot out from the shelves; these will injure him if not avoided, and are not to be confused with the books with teeth that attack Mario in other rooms. Once the plumber has rounded the corner, he will come to a wall with three books jutting out of the wall. If Mario punches or kicks them in the right order, the wall will move away revealing a door. If he hits the books in an incorrect order, a small book will attack him and the books will reset. Once he enters through the door, he will be able to claim this mission's Power Star.

Star 4: Seek the 8 Red Coins
Mario has to go back to the first level, destroy the Big Boo once more, and then collect the eight Red Coins scattered about the level. This mission is the same in both Super Mario 64 and its remake, except for the fact that in Super Mario 64 DS, one Red Coin is floating, and not under a tombstone like all the rest.

Star 5: Big Boo's Balcony
Mario's next journey takes him to another encounter with Big Boo. He'll head up to the third floor and see a door that will lead to the outside balcony, where he will meet Big Boo once again. After his third defeat, Big Boo will give up yet another Power Star. The Star will jump up to the roof of the house, and Mario will have to get up to retrieve it.

In Super Mario 64 DS, the level is the same as in the original, however it should be noted that the Star can only be retrieved by Mario or Luigi, as Wario is unable to jump high or wall kick.

Star 6: Eye to Eye in the Secret Room
Back on the third floor, Mario will see a wall with a picture of a Boo. The power star he seeks is inside. What he must do is to have activated the blue ! Switch and to be able to use the Vanish Cap located on the second floor. He needs to quickly acquire the cap and rush through the wall on the third floor, where Big Mr. I resides. Once Mario defeats it, he will be rewarded with another Power Star.

Like with Star 5, this level is the same in Super Mario 64 DS as it is in the original, but must be completed using Luigi, as he is the only one who can turn invisible (using a Power Flower, not a Vanish Cap).

Star 7 (DS): Switch Star in the Basement
As a mission exclusive to Super Mario 64 DS, this one requires Wario to complete the level. In the basement, there is a black box that only Wario can break. Underneath is a Star Switch that will activate the Star, which Mario or Luigi (Get a cap to become Mario or Luigi) must then travel to and collect before the time runs out.

Differences in the DS Version

 * In Super Mario 64 DS, the player could still find King Boo, and although he is a large boo with a crown, he was still named "Big Boo" (even though the game was released after Luigi's Mansion).
 * At the top floor of the mansion, there is a Luigi painting that leads to the Big Boo Battle. Mario can access this by turning into Balloon Mario by hitting the Red ! Block, or by doing a wall kick. Luigi and Wario can back flip off the top of the Flower Box.

Trivia

 * Whenever Mario defeated a ghost in the first star mission, "Go on a Ghost Hunt", of the level, Big Boo (or King Boo) would deliver the message, "Ghosts...don't...die! Can you get out of here ALIVE?" After the last ghost is defeated, he sends another message.
 * Big Boo's Haunt is the only course that does not share a theme with another course.
 * A remix of the merry-go-round's theme is in Mario Strikers Charged Football as Boo's theme whenever he scores a goal.
 * In Super Mario 64 DS, this is the only main course that Yoshi can't access at all; he can't defeat Boos in this game, nor can he eat any.
 * The music for the Merry-Go-Round is later reused in the New Super Mario Bros. minigame Lakitu Launch.