Boomerang Bros. are a counterpart to the Hammer Bros. Unlike the Hammer Bros. however, Boomerang Bros. prefer to throw Boomerangs at their foes. Boomerang Bros. are more deadly however as their projectiles (the boomerangs) will fly back after being tossed requiring extra caution. Yoshi however, can swallow their Boomerangs for his own use.
Boomerang Bros. are seen in New Super Mario Bros. Wii where they are commonly found in World 2. A couple are seen throughout the level tossing their Boomerangs at any foes. They hop around slightly less than their cousins do. Defeating a Boomerang Bro. is easy however, either stomp on them or use a fireball/iceball.
Boomerang Bros. appear yet again in Super Mario Galaxy 2 usually stationed in the Bowser and Bowser Jr. Galaxies. They attack by tossing their Boomerangs as usual. Any attack can stun a Boomerang Bro., they can then be rammed to defeat them. Yoshi can swallow one of their Boomerangs to spit out as his own projectile.
Boomerang Bros. return in New Super Mario Bros. U with the same behavior as in New Super Mario Bros. Wii. In this game, they are commonly found in Meringue Clouds. Just as before, any attack can defeat them.