Knockback Bros.

Knockback Bros. is a Bros. Attack used by Mario and Luigi during the events of Mario & Luigi: Superstar Saga. The move costs five BP on Modes 1 and 2, and three BP on Mode 3. Luigi learns this move. Luigi smacks Mario with his hammer, making him a ball, and hits him like a golf ball. The buttons pressed are to whack Mario,  again to send him shooting toward an enemy, and  to do damage to the enemy.

After successfully executing the attack forty-three times, Mario and Luigi learn the Advanced version. In the Advanced version, more controls are added. The controls for the standard version are the same, but to execute the Advanced version, must be pressed immediately after the first  press. Then the controls are to hit Mario,  to do damage,  to hit Mario,  to do damage, etc.

This move is also used by the Hammer Bros. in Mario & Luigi: Partners in Time, where they perform it exactly the same as the Hammer Bros. did in Superstar Saga. They use it when under influence of the Shroobs mind-control helmets, and are only able to perform it together with both Hammer Bros. standing. Occasionally, their hammers will break, causing the other Hammer Bro to bounce towards Baby Mario and Baby Luigi. To dodge the attack, the Baby Bros. must jump over the Hammer Bro that was hit at them.