Big Boo Battle is an additional level exclusive to Super Mario 64 DS. The entrance to the level is found through the Luigi painting in Big Boo's Haunt's third floor. The level is accessible to anyone other than Yoshi, as Yoshi can't enter Big Boo's Haunt since cannot defeat the Big Boo in the castle's courtyard to enter the leve;. After defeating King Boo (who is erroneously called "Big Boo" in the English version) at the end of the level, the player is rewarded with the Luigi Key to unlock Luigi. Initially, only Mario can enter the course, as Luigi is needed to unlock Wario. It is one of the only two secret levels in the game to be inside a main level; the other being Behind the Waterfall in Hazy Maze Cave, as well as the only level within another level in the game where another playable character can be rescued.
Throughout the course, the player can hear King Boo's laugh echoing through the rooms. The rooms are set up like a maze, and if the player goes through the wrong door or falls down a hole, they are returned to the starting room without losing a life.
The player starts in a circular room with a Boo, a rotating pyramid in the center, and a rotating platform around the walls of the room (similar to Big Boo's Merry-Go-Round). Taking the door on the right leads to a square room with falling bridges and a Mr. I in the center. The room to the north has a large tilting platform with a ? Block over top of it, which allows the player to collect the Coins above with the Power Flower inside. Additionally, a Luigi Cap can be found in this room if he is unlocked. The room to the east has a large pit with lifts that help the player move across the platforms; a Wario Cap can also be found in this room if he is unlocked. The final room to the north is a large hall with a falling bridge in the center. At the end of the bridge are several lifts that help the player over the wall and to the hole leading to the arena with King Boo.
King Boo Battle
Upon falling into the hole, the player is brought to a room with a large mirror. Approaching the mirror and pressing the "X" Button to look into it, the reflection of the player turns into Luigi, though nothing happens if Luigi is already rescued. After the reflection change, King Boo appears next to the player and begin a short dialogue. Once the dialogue is over, King Boo begins attacking.
At first, King Boo is only visible on the other side of the mirror, though a large shadow is visible on the player's side. Using this, the player can sneak up behind King Boo and attack. After the first hit, King Boo becomes visible on the player's side, and then becomes visible on the reflection's side after the second hit. After attacking King Boo three times, he is defeated and drops the Luigi Key.
King Boo's methods of attacks are simply running into the player or shooting a blue fireball, the latter of which only happens if King Boo is on the player's side of the mirror. Like with other Boos, King Boo turns invisible and becomes unable to be attacked if the player character looks at him. If the player doesn't attack King Boo quickly enough, he teleports to the side of the mirror opposite of the one he is currently on. When on the player's side of the mirror, he is not reflected in the mirror nor does a shadow appear on the opposite side. Additionally, King Boo moves faster with each phase. There are rows of Coins along the walls, letting the player recover damage.
Similar to the large mirror in Peach's Castle, the Camera Lakitu can be seen in the mirror's reflection.
There are two Power Stars that the player can collect in this level.
Located throughout the level are the eight Red Coins. In order to collect them all, the player needs to have the Power Flower and Wario unlocked. Once all the Red Coins are collected, the Power Star appears at the Star Marker in the large hall with the falling bridge. The location of all the Red Coins are:
- In the first room, opposite of the player's starting position.
- Two are in the next room: one on the platform with the Mr. I and one over the falling bridge to the east.
- Two are in the next room: one on the platform to the east and one in the air in the back-right corner. The one in the air can either be accessed with Balloon Mario or with a triple-jump performed by either Mario or Luigi.
- Two are in the next room, both of which require the use of the lifts to collect.
- The final Red Coin is under the Black Brick Block in the next room, which only Wario can destroy.
There is a hidden Star behind the Boo portrait in the last room before the boss. To collect it, the player needs to go to the room with the ? Block and grab the Luigi Cap if they aren't already playing as Luigi. As Luigi, the player needs to grab the Power Flower from the ? Block, which turns them invisible. Before the power-up wears off, the player needs to quickly move through the rooms and jump through the large Boo portrait after the falling bridge to collect the Power Star. To leave the small room, the player can simply walk though the portrait again.
- In the final room of the level, there are three Boos that, unlike the other Boos throughout the level, can respawn after they are killed, as well as retaining their Coins. If the player were to fall into a pit or enter one of the wrong doors in the maze they would be able to collect the same coins again. This means that there are technically an infinite number of Coins to be collected within the level, but the player will still not receive a Power Star unlike the main levels.
- Depending on which of the three unlockable characters the player plays as, King Boo will talk to each one differently, like King Bob-omb, Goomboss, and Chief Chilly.
|Super Mario 64 and Super Mario 64 DS locations|
|Battle Fort* • Big Boo Battle* • Big Boo's Haunt • Bob-omb Battlefield • Bowser in the Dark World • Bowser in the Fire Sea • Bowser in the Sky • Cavern of the Metal Cap/Behind the Waterfall • Chief Chilly Challenge* • Cool, Cool Mountain • Dire, Dire Docks • Goomboss Battle* • Hazy Maze Cave • Jolly Roger Bay • Lethal Lava Land • The Princess's Secret Slide • Rainbow Ride • Rec. Room* • Shifting Sand Land • Snowman's Land • Sunshine Isles* • Tall, Tall Mountain • The Secret Aquarium • Tick Tock Clock • Tiny-Huge Island • Tower of the Wing Cap/? Switch • Vanish Cap Under the Moat/The Secret Under the Moat • Wet-Dry World • Whomp's Fortress • Wing Mario Over the Rainbow/Over the Rainbows|
|* Exclusive to the Nintendo DS version.|