Rabbit
Rabbits of the Mushroom Kingdom, much like their "Real World" counterparts, are small, furry mammals with long ears and large hind paws. They're common in the fields and wooded regions of the kingdom. These animals also feature quite prominently in several Mario games. In Super Mario Land 2: 6 Golden Coins, Mario could become Rabbit Mario by eating a Carrot. While in this form, Mario could use his newfound rabbit ears to hover momentarily while falling or jumping.
In Super Mario 64, a yellow rabbit named MIPS could be found in the basement of Peach's Castle. If caught, he would give Mario a secret Power Star. In Super Mario 64 DS, rabbits feature much more prominently. They are found throughout the castle grounds (and their locations vary from character to character). The designated rabbits for each character have a specific color - yellow for Yoshi, pink for Mario, green for Luigi, and orange for Wario. If caught, they would unlock mini-games for the player to play in the Rec-Room. Special glowing white rabbits needed to be caught to unlock a white door in the Character Door room, behind which was a secret Power Star.
Rabbits are also a Species in Super Mario Galaxy. Some (at the least) are really Cosmic Toads. Space Rabbits are found all around the galaxy, helping Mario through his journey. They have stars on the ends of their ears and come in different colours.
The Space Rabbits help guide Mario around and help him solve puzzles in the galaxy; they often are in groups. They may have a Star Shard to offer, maybe a Star, a tip, or perhaps a little guidance.
Mario has also been seen catching rabbits for stars, which could mean that although some rabbits are really Toads, others might work for "The Creature" [1].
