From the Super Mario Wiki
Boomerang Mario is a transformation introduced in Super Mario 3D Land, and returns in Super Mario 3D World. It is based on the Boomerang Bro, making it similar to Hammer Mario, which is based on the Hammer Bro. Mario becomes Boomerang Mario after obtaining a Boomerang Flower. With the Boomerang suit, Mario can throw one boomerang at a time to defeat enemies, destroy projectiles, and collect items from a distance. Mario can also jump and move away from it to dodge the boomerang and allow it to move back and forth continuously before collecting it. If a Boomerang is destroyed in any way while one is being tossed, Mario must wait a moment before he can toss another (a brief glimmer of light signifies that he can toss another boomerang). Unlike the Hammer Suit, Boomerang Mario can only defeat enemies Fire Mario can defeat (as well as Bullet Bills and Banzai Bills).
In Super Mario 3D World, the boomerang has a larger range, and both it and the armor are now colored depending on the character using the power-up (red for Mario, green for Luigi, pink for Peach, blue for Toad, and cyan for Rosalina; Mario, however, still has the blue shell).
Super Smash Bros. for Nintendo 3DS Trophy information
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