Gold Mario

Gold Mario is a form debuting in New Super Mario Bros. 2, acquired by grabbing a Gold Flower. In this form, Mario can shoot big golden fireballs, defeating any enemy or breaking any block they touch, turning them into coins.

After becoming Gold Mario, the character becomes a glowing statue made of pure gold. This appearance resembles a golden Metal Mario, or a golden Ice Mario from Super Mario Galaxy. If Mario crosses the Flagpole as Gold Mario, he will become Fire Mario.

Luigi gains a similar form, but it is metallic silver, much more like the Metal Mario.

Trivia

 * In the first Animal Crossing game, there are two furniture items based off of Mario and Luigi, them being the Mario Statue and Luigi Statue. Interestingly, the Mario Statue is golden and the Luigi Statue is silver, similar to this power-up.