Super Leaf

A Super Leaf is one of the many power-up items in the Mario series. Super Leaves originated in the game Super Mario Bros. 3. Super Leaves turn Mario into Raccoon Mario. As such, Mario or Luigi will grow raccoon ears and a raccoon tail. This tail has many functions. A move of the Super Leaf is using the tail the Bros. get to spin nearby enemies by pressing the Button. Second, if Mario or Luigi is in the air, he can descend slowly by wagging the tail. Third, Mario and Luigi can use the tail to hit a ? Block/Brick Block to make the item pop out or break the Brick Block.

Super Mario Bros. 3
Super Leaves first in the game Super Mario Bros. 3. The item transforms Mario or Luigi into Raccoon Mario or Raccoon Luigi (respectively). If they run for long enough, the P-Meter will become full. When this happens, they can jump and fly by holding. They can also float down slowly by holding. If they hit, they will swing their tails, which can activate ? Blocks and kill enemies.

Super Mario 3D Land
After a long hiatus, Super Leaves reappear in Super Mario 3D Land; however, they turn Mario into Tanooki Mario, and Luigi into Kitsune Luigi (a.k.a. "Tanooki Luigi"). In spite of the change, the Tanooki forms granted by Super Leaves still act as Raccoon Mario, and Bowser's forces are given "Raccoon" forms from the Super Leaves he's stolen. Additionally, the leaves in this game were redesigned by being given strips, eyes and a "bite" mark. They are also more involved with the storyline of the game, rather than just being a mere a power-up. It is revealed at the intro that Mushroom Kingdom's Super Leaves grow from a rare tree called the Tail Tree (on account of its oddly-shaped bough). During a storm, Bowser stole all of the tree's mythical leaves by blowing them up from the tree, using them to power-up his minions and bestowing them with tails to attack and float around. There is also a variation of the Super Leaf in the game called the Invincibility Leaf, that, not only gives Mario a glowing, white Tanooki form, but also makes him invincible. Mario can only obtain this if the player has lost five lives in a level. Another item similar to the Super Leaf is the Statue Leaf, which allows Mario to turn into a statue for an certain amount of time (essentially reverting to the original Tanooki Suit, except it also functions as a Ground Pound and lasts much longer). Also, the new artwork makes the Super Leaf look similar to the symbol of the Animal Crossing series.

New Super Mario Bros. 2
Super Leaves also appear in the side-scrolling Mario game, New Super Mario Bros. 2, having the same design from Super Mario 3D Land and Mario Kart 7. Unlike in Super Mario 3D Land, they retain their original effects from Super Mario Bros. 3 and turn Mario or Luigi into Raccoon Mario or Raccoon Luigi, respectively. However, Luigi keeps his Japanese fox (kitsune) tail and ears that were first seen in Super Mario 3D Land in his Tanooki Suit, or in his case, a "Kitsune Suit". While in this form, the P-Meter appears in the bottom left corner of the top screen and Mario can run for long enough to fill it up to fly by holding or. He can also glide down by holding or. He can swing his tail with or  to activate ? Blocks and kill enemies. In addition, if Mario loses five lives in a level, a block with an Invincibility Leaf inside appears, just like in Super Mario 3D Land. The only difference is that it changes Mario or Luigi into White Raccoon Mario or White Raccoon Luigi, respectively. In this form, Mario is invincible and the P-Meter fills up much faster. He can still be killed by lava, bottemless pits or by being squished between two walls, though.

Mario Kart series
The Super Leaf can be seen as the logo for the Leaf Cup in Mario Kart DS, Mario Kart Wii and Mario Kart 7. Mario Kart 7 uses the 3D Land design for the logo.

Mario Kart 7
Super Leaves appear as an actual item in Mario Kart 7. Here, they create a tanooki tail on the back of the kart which doubles as an offensive and defensive feature. Pressing or  swings the tail which can hit other karts and protect the player's kart from other items such as Green Shells. When activated, the Super Leaf lasts for 10 seconds, or until the player is hit by an item.

Trivia

 * In the NES version of Super Mario Bros. 3, Super Leaves were green while in the inventory or taken inside Toad Houses, and brown when found in a level. In reference to this, in Super Mario 3D Land, the Super Leaves fresh on the Tail Tree are a lively green.
 * What appear to be small, green Super Leaves can be seen on the head of the Tanoomba and Tashrooba enemies from Mario & Luigi: Superstar Saga and Mario & Luigi: Partners in Time.
 * According to the comic book story "It's Always Fair Weather", Super Leaves are grown on a plant labeled as "Magic Leaf Raccoonius".
 * In Super Mario 3D Land, Super Leaves are seen in a tree. This tree may be one of this species.
 * In "Sneaky Lying Cheating Giant Ninja Koopas", Mario and Luigi managed to find a huge Super Leaf hidden within an equally large Block in Giant Land. Due to the Super Leaf's size, Mario and Luigi were both seemingly able to obtain Raccoon Power by touching the single leaf at the same time.
 * Super Leaves were originally supposed to be in Paper Mario Sticker Star, but were taken out and replaced with Leaf stickers and Shiny Leaf stickers.
 * The emblem of the Animal Crossing series looks very similar to the current design of the Super Leaf, albeit without the eyes and stripes.