Ice Bro

Ice Bros. are rare sub-species of Hammer Bro. introduced in World 3 of New Super Mario Bros. Wii. Ice Bros. resemble ordinary Hammer Bros., but with light blue shoes, shells and helmets, and instead of throwing hammers, they will throw Ice Balls at their enemies (similar to how Fire Bros. throw Fireballs). If Mario, Luigi, Blue Toad, or Yellow Toad get hit by one of their Ice Balls, they will freeze in a block of ice for a moment.

New Super Mario Bros. Wii
Ice Bros. appear in World 3 of New Super Mario Bros. Wii. They are the enemies in the Enemy Course. As aforementioned, they use Ice Balls as weapons to harm and freeze the gang (even freezing other enemies, including others of their species). Like most of their related species, they usually attack in a group of their members. If a Yoshi catches one of their Ice Balls, the Yoshi can spit it out in the form of a blue fireball that freezes anything in its path.

New Super Mario Bros. U
Ice Bros. reappear in New Super Mario Bros. U. They are found in Frosted Glacier. They behave the same way they did in New Super Mario Bros. Wii, where they attempt to freeze a playable character by throwing Ice Balls.

Paper Mario: Sticker Star
Ice Bros. make their Paper Mario debut in Paper Mario: Sticker Star for the Nintendo 3DS. Ice Bros. look just like they did in New Super Mario Bros. Wii. They are semi-common enemies in World 4. Unlike New Super Mario Bros. Wii, they spit out Ice Balls instead of throwing them, much like Fire Bros.. The Ice Balls can freeze Mario for a few seconds.