MIPS The Rabbit

MIPS the Rabbit is a rabbit that appears in the Castle Basement of Super Mario 64 exclusively. They are a yellow rabbit with a tired expression, yellow eyelids, a black nose, and a single tooth. They appear after the player collects 15 stars in front of the Lethal Lava Land painting, and runs away when Mario walks nearby. When caught, they give the player a star. MIPS the Rabbit appears again with the same formula when the player obtains 50 stars.

MIPS Throwing
There was an unused mechanic where the player would be able to throw MIPS by his ears. This was not included likely due to time constraints, and animal abuse issues. In the files of Super Mario 64 is also an unused animation of MIPS bouncing, likely due to being thrown. It is possible to throw MIPS by clipping into the room where the player drains the moat with MIPS and going into the water. The Personalization A.I. can also add MIPS throwing into the game.

MIPS Clip
There is a glitch the player can perform while holding MIPS to clip through doors. This glitch is performed by turning around by crawling at a precise angle and grabbing MIPS. This is often used in 16 star speedruns to enter Dire, Dire Docks early.

MIPS Forest
MIPS Forest is the name given to an area seen in a mysterious image that includes MIPS the Rabbit. It is seen in an image explaining an extended version of the Super Mario 64 iceberg. The origins of the image are unclear, though it is speculated to take place in Big Boo's Forest. In the image, MIPS says to Mario, "Are you lost? You REALLY shouldn't be walking around in unknown places!~" It is currently unclear what this message means.

MIPS Following
MIPS Following is the name given to an anomaly where MIPS the Rabbit has a bigger role in Super Mario 64. This usually manifests as MIPS the Rabbit following the player in a level, or giving tips to the player, similarly to the MIPS Forest image. This is real unused content seen in earlier builds of Super Mario 64.

Pink MIPS
Found in the files of Super Mario 64 is an early model of MIPS The Rabbit that is pink, possibly later inspiring the Pink Rabbit.

Trivia

 * In Super Mario 64 DS, MIPS the Rabbit was replaced by the colored Rabbits. Notably, Yoshi's rabbits share a similar coloration to MIPS the Rabbit, and some Rabbits appear in the same location as MIPS the Rabbits. Notably, the Rabbits are internally known as "MIP" and the star keys they drop are known as "MIP Keys".