The second Bros. Attack for Mario & Luigi: Dream Team is called the Bye-Bye Cannon. It is found in the Wakeport area and costs 7 BP.

Whenever you begin the attack, Mario and Luigi and 2 clones of each of them will get shot out of the Bye-Bye Cannon at a randomized order. Remembering the order is important for this attack as you will need to in order to defeat the enemies.

You will have to jump on the enemies in the same exact order the Bros. were shot out of the cannon in order to deliver maximum damage. If performed correctly, the player must do the attack again in reverse order in the form of a giant Spin Jump to obtain Excellent status. While Mario using 3DS A.svg.png and Luigi using 3DS B.svg.png.

The Bye-Bye Cannon deals critical damage to enemies that are weak to jump attacks. This includes Mammoshka, Mammoshka X, and Dreamy Bowser.