Created and piloted by Dr. Robotnik, the Ball Shooter is a machine that has two underwhelmed cannons above the upraised mobile, from where Dr. Robotnik is piloting it. These cannons shoot black cannonballs after opening one of two hatches. The mobile of the Ball Shooter itself is set high enough to be not reached with a Spin Jump.
After the player gets close to the Death Egg, Dr. Robotnik jumps on the Ball Shooter and starts firing a cannonball from one of two hatches below the hill. When the cannonball gets fired from the lower hatch, it will roll to the left side of the screen. However, due to not gaining enough momentum on the left uphill grade, it will roll back and crash into the closed hatch wall. The Ball Shooter's upper hatch can fire two ways, as it can fire cannonballs far off-screen where they break to pieces or does not shoot far enough, causing the cannonballs to roll back into the lower hatch's wall in a similar way.
Cannonballs are only things that can damage the player aside of touching the Ball Shooter without using Spin Jump. When the Ball Shooter is ready to fire cannonballs, the hatch door generally raises up, where it acts as a platform whilst horizontal and will help the player reach the cockpit to hit the Ball Shooter. However, if the player has a Lightning Shield equipped during the battle, he/she can easily get to the cockpit by double jumping and continuously attacking.
Like many other regular bosses, eight hits are required to defeat this boss. Upon the Ball Shooter's destruction, Robotnik falls down along with destroyed Ball Shooter. After that, the player will find an Egg Mobile that the playable character can use to progress to below the Death Egg and the next boss.
Ball Shooter's mobile has small turrets, which Dr. Robotnik never uses during the fight.
There is a glitch where Tails gets stuck under Ball Shooter if the player has been using Sonic and Tails as playable characters, and make for an easy win as he jumps repeatedly trying to get out, but ends up damaging the Ball Shooter.
This is the only Act Two boss in Sonic the Hedgehog 3 that does not incorporate Robotnik's Egg Mobile.