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.

Trivia

 * The "special attack" of the L33t Hamm3r Broz. is similar to Knockback Bros.