Bounce Bros. is Luigi's first Bros. Attack in Mario & Luigi: Superstar Saga. It is learned alongside Splash Bros. in the Stardust Fields. The move costs 4 Bros. Points in mode 1 and mode 2, but costs 3 in mode 3.
In Bounce Bros., Luigi jumps high off of Mario's back, going off-screen. Mario will jump and grab his legs. They will flip and slam into the enemy.
It takes 8 uses of Bounce Bros. before learning the Advanced Command. In the Advanced Command, Mario and Luigi jump on two different targets.