Factory Boss

''This page is about the boss. You may be looking for the stage.''

The Factory Boss (also called Robot Boss) is the third boss in the Red Ball 4 series and the final boss of the web versions as well as the main storyline. It is the boss of the "Box Factory" episode.

Appearance
The Factory Boss is a large metal box with razor blades spinning along its surface which stop when it's stunned or hurt. It has two red mechanical eyes, and a greasy wide mouth full of yellowish teeth, which are flat unlike most other Boxes.

When in its vulnerable state, its expression changes: its eyes turn yellow and instead of looking angry, it starts hyperventilating. In the original browser version his left eye will flicker as if it's broken, but this isn't so in the mobile version.

Sequence
First Phase: The boss will smash the ground and roll off-screen, activating 5 of the 6 Punch Presses at the top of the screen in a wave manner, starting from the opposite side that the boss retreated to with the last one in the wave not stomping. The boss will now come out of the opposite side in its vulnerable state, giving the player a chance to hurt it. This phase will repeat until the boss is left with 3 hearts.

Second Phase: The boss will remain off-screen for the entire phase, with the only hazard being the Punch Presses. It will first activate the 3rd and 4th presses, then it will activate the 2nd and 5th, then activate the 1st, 3rd and 5th, then activate the 2nd, 4th and 6th, and finally end the phase by activating all presses except the 3rd and 4th.

Third Phase: The boss will now emerge from the right side, then smash the ground and spawn a Boom Box on the opposite side facing the player; after the spawned box has detonated, the boss will retreat and switch sides. This phase will repeat until the boss's health is completely depleted.

In this phase the boss will never become vulnerable, and the only way to harm it will be via the Boom Boxes it spawns; this means that the player will have to make the spawned enemies explode on the boss in order to beat this phase.

Trivia

 * The Factory Boss is currently the only boss that is seen getting damaged by its own minions.
 * Factory Boss shares his battle music with Cave Boss.
 * He is the first boss to be spiky, with the second one being Cave Boss.
 * Unlike the Boom Box, this box changes facial expressions despite also being a robot.