The Statue Leaf is a power-up that appears in Super Mario 3D Land. It turns Mario and Luigi into their Tanooki forms, with both of them wearing a scarf of their respective color, and gives them the ability to turn into a statue in place of doing a ground-pound. This makes it similar to the Tanooki Suit from Super Mario Bros. 3, but without the ability to fly or transform on the ground.
The Statue Leaf only appears in the Special Worlds, replacing the Super Leaf therein. It's first appearance is in the first level of the first Special World.