Cannonballers are powerful Bros. Items used to attack one enemy in Mario & Luigi: Sibling Rivalry. All two Bros. must be available to use this item. The Bros. Jump into a cannon, are shot out in a random order, and then land upon the same foe one at a time. The player must press each brother's selected button right when they are about to hit the enemy, then they go in a second time and the attack is repeated. If this is not done, less damage will be dealt.