Fire Mario is the ability obtained by Mario, Luigi, Peach, Toad, or Rosalina in the 3D Mario games. To obtain this ability, the character must first collect a Fire Flower. Strangely, the fireballs thrown with the ability can be thrown underwater.
In Super Mario Galaxy and Super Mario Galaxy 2 Edit
The fire ability does not make a 3D Mario appearance until the Galaxy games. In these games, you only have a certain amount of time to use the Fire Flower until it disappears and you can no longer throw fireballs. Also, the spin function cannot be used as throwing the fireballs requires shaking the Wii Remote. In these games, they are often used to destroy crates in order to assist the Gearmos.
In Super Mario 3D Land and Super Mario 3D World Edit
The Fire Flower seen in these games is much more like the traditional 2D side scrolling games as compared to the Galaxy series. They no longer have a time limit and the fireballs can bounce off walls.