Big Piranha Battle

Big Piranha Battle is a supposed level in Super Mario 64 DS that unlocks Waluigi when finished. It is described as an area similar to Goomboss Battle filled with Piranha Plants. It's boss is the Big Piranha Plant. The level does not have a consistent location.

Geography
The level is often described as a large, bright area with several tree trunks, similarly to Goomboss Battle, though the poison gas is replaced with a large death plane. In the center of the map is a large tree trunk with a vine leading up to the boss battle in the sky. The level's enemies are usually Piranha Flowers, Piranha Plants, and Goombas. The main geography of the level is not consistent past this point. The skybox is described as a brighter version of Goomboss Battle's skybox with living trees.

Boss Battle
The boss battle is reached by climbing the vine in the center of the map into the sky. It takes place on the same arena as Goomboss Battle, with the boss, the Big Piranha Plant, in the poisonous center of the arena. It appears sleeping when the player enters the level, but wakes up in a cutscene immediately after. It does not have any dialogue, and the fight starts after the Big Piranha Plant wakes up.

The Big Piranha Plant's attacks are attempting to bite the player, and shooting fireballs at the player. Several Piranha Plants dot the arena, and killing all of them can cause a Giant Mushroom to appear in front of the Big Piranha Plant. Using it, the player can jump on top of the Big Piranha Plant, dealing damage to the boss, though immediately removing the Giant Mushroom's effects and respawning all of the Piranha Plants. This must be repeated 2 more times for the boss to be defeated. It will then shrink down out of sight, and it will then drop the key for Waluigi.

Star 1
This star is found by collecting 8 red coins throughout the level.

Star 2
This star is found by pressing a star switch and reaching the star before the timer ends.