Statue Mario

Statue Mario is a form of Mario or Luigi first appearing in Super Mario Bros. 3. While in this form, the Mario Bros. are invincible to all enemies, though they are immobile. In Super Mario 3D World, when Mario obtains a Lucky Bell and turns into Lucky Cat Mario, he can transform into Golden Statue Mario, which functions similarly to Statue Mario, but Mario earns coins in that form.

Super Mario Bros. 3
Statue Mario debuted as a form of Tanooki Mario, which also provided flight and transformation on the ground. As a statue, Tanooki Mario cannot be hurt, and if he uses this ability in the air, he can slam down like a Thwomp. This can destroy many enemies, instantly destroying all Goombas and enemies with throwable shells (like Koopas, Buzzy Beetles, and Spinies). It can also stomp previously unstompable enemies like Piranha Plants, Piranhacus Gigantici, Venus Fire Traps, Spiny Eggs, Thwomps, Podoboos, Fire Snakes, and Chain Chomps.

The Statue form is also the only way to destroy Roto-Discs and Rocket Engine flames. Statue Mario will sink rapidly underwater, and can even oppose some pipes' upward currents. This allows Mario to stomp Lava Lotuses, Bloopers and fish enemies underwater. Boss Bass is the only fish that Mario can't stomp on, and the only enemy that can defeat him in that form by eating him. In Super Mario All-Stars, Tweester can turn Statue Mario back into Tanooki Mario on contact. He can still turn into the statue while in the Tweester, but it will not free him or have any desirable effect. One setback is that while Mario is a statue, he cannot move. In the ending, a Koopa Troopa can be seen comically praying before Statue Mario as if he was a religious idol.

Super Mario 3D Land
In this game, due to the absence of Raccoon Mario and the Tanooki Suit, Statue Mario or Luigi became a separate form, and can only be used with a Statue Leaf, which replaces the Super Leaf in the Special Worlds' levels. The statue now looks similar to Tanooki Mario or Kitsune Luigi, except with an extra red or green bandana respectively. The statue transformation replaces the Ground Pound in this game. The longer or  is held, the longer the brothers will stay in statue form. When Statue Mario shakes in about two seconds, he reverts to Tanooki form.

The statue form has many functions, primarily, it will protect the brothers from any hazards in the level, except for lava or the time running out. It can also take out almost every enemy that cannot be defeated with a normal pound. Enemies will also stop attacking or following the Mario Bros. in statue form.

New Super Mario Bros. 2
While the form itself doesn't appear in the game, in the final levels of New Super Mario Bros. 2, the Koopalings show up and try to turn Mario/Luigi into stone with a blinding light from the Koopa Clown Car. Unlike the proper statue form, this state is involuntary and serves as a hindrance, which Mario/Luigi must avoid by hiding behind walls in the background. If they are turned to stone, the player must mash the buttons to revert to normal.

Super Mario-Kun
Statue Mario appears in Super Mario-Kun. Instead of using a Tanooki Suit, Mario and Luigi transform into stone due to a sphinx-like creature with a Thwomp for a face. However, only Mario resembles the Super Mario Bros. 3 statue, and unlike in the games, Mario can move and even fight his enemies as a statue.

Trivia

 * According to the comic book story "Tanooki Suits Me", the Tanooki Suit's statue transformation is triggered by pressing a button on the front of the suit, and to change back, one has to simply wish he or she were human again.
 * In Super Mario 3D Land, as a statue, Mario holds up his right hand, while Luigi holds up his left. Also, Statue Mario closely resembles a real lucky cat.
 * This distinction is most likely being referenced again in Super Mario 3D World, where Golden Statue Luigi raises his left paw while the other characters raise their right paw.
 * The effect of the Stone Cap in Paper Mario is similar to Statue Mario, as it transforms Mario into a stone statue that is invincible, yet immobile.