Ice Bro

Ice Bros. are rare sub-species of Hammer Bro. debut in New Super Mario Bros. Wii. Ice Bros. resemble ordinary Hammer Bros., but with light blue/pure white shoes, shells and helmets, and instead of throwing hammers, they will throw Ice Balls at their enemies (similar to how Fire Bros. throw Fireballs).

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 a playable character (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, where they are found in only one level in Frosted Glacier called Icicle Caverns in which there are only 2 of them. 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. Like in New Super Mario Bros. Wii, they throw Ice Balls and try to hit Mario. The Ice Balls can freeze Mario for a few seconds. They later appear in the first area of Rugged Road after Mario has placed an ice based thing sticker or else they are Fire Bros. This game may prove that Ice Bros. are indeed, Fire Bros after being in a cold area.