After completing every previous level in Octo Valley, the Boss Kettle on the UFO floating above Octo Valley will be unlocked. At the very top of Area 5 is a launchpad to Super Jump to the UFO, which will fly off into the sky when Agent 3 enters its Boss Kettle.
This boss fight uses everything the player has learned throughout their missions in Octo Valley. During the boss fight, DJ Octavio uses several moves to attack Agent 3:
- Octorpedoes - airborne Octopods shot out from the four cannons on the front. They home in on the player, but can easily be evaded or destroyed. They spread a small amount of ink if they land.
- Two giant fists that can be extended to try and punch the player. If shot at before they hit the ground, they will fly back into the machine and damage it, pushing it backwards.
- Small projectiles that resemble disco balls. If they hit the ground, they will spawn an enemy. If they are shot before then, they will harmlessly explode in midair and nothing will spawn. The type of spawned enemies depends on which phase of the fight the player is on, with Octocopters and Octobombers initially, Octoballs in the second phase, and Twintacle Octotroopers in the final phase.
- Killer Wail. Unlike the Inklings' Special Weapon of the same name, this variation is smaller and takes longer to charge up.
- A massive, octopus-shaped bomb that explodes into a huge amount of enemy ink if it lands. If it is shot back at DJ Octavio, he will punch it back at the player twice - he then runs out of fists and will be hit by it. These bombs are necessary for damaging DJ Octavio greatly and defeating him.
First, DJ Octavio will send out two Octorpedoes at a time which can easily be avoided by hiding in your ink. Eventually, one of the fists from the machine will be fired at you. If you carefully watch DJ Octavio's hands, you can see which one is going to punch you next, as it will rumble. As soon as it fires and is in range, shoot ink at it until it reverses into DJ Octavio. Strike him three times and he reveals a large octopus-shaped missile. Fire at this and he will punch it back at you. Repeat this two more times and a launchpad will appear to take you to the next phase. The bomb will gradually get faster each time, especially in the later phases.
DJ Octavio will now throw both fists at once, as well as shooting the Octarian version of the Killer Wail every so often. Boxes containing armor appear on various platforms. The Sunken Scroll for the boss is in a small box on the third platform. In order to get close enough to DJ Octavio to fight him, you must use the Propeller Lifts to get to other platforms. While it is possible to get very close to the machine, it is not recommended to do so, since all attacks will be harder to defend against and his barrier will stop you. Shoot his fists back at him six times and he will release the missile. Once you send the missile into his machine three times, another launchpad will appear.
Along with the increased amount of Octorpedoes being shot at a time, bombs resembling disco balls will also be thrown and will spawn Octocopters and Octobombers if they manage to hit the platform. Some platforms are invisible and require you to shoot your ink to proceed. To reach higher platforms, you must use Gushers. Continue to repeat the main strategy in the previous phases.
The enemy bombs will now only spawn Octoballs, and four Octorpedoes will be shot at a time. DJ Octavio will shoot lasers every few seconds. Platforms are now noticeably narrower and therefore harder to avoid DJ Octavio's many attacks. There are common Balloon Fish to spread ink all over the platforms and hide from attacks. Continue to repeat the main strategy in the previous phases.
After the Squid Sisters override the boss music and Cap'n Cuttlefish sets himself free, DJ Octavio becomes extremely aggressive. Only one enemy-spawning bomb is fired at a time, spawning a Twintacle Octotrooper, and large amounts of Octorpedoes are fired over time. There are Inkrails connecting each platform. The final missile requires quick movement as it is at its quickest speed. Once you reverse the missile three times, DJ Octavio will eject from the machine. Shooting your ink at him will thrust him back at his machine, ending the battle.
- Ink as much ground as you can so that you can dodge attacks easily.
- Try and burst Octavio's enemy-spawning bombs before they hit the ground.
- Collect lots of armor. When getting to the last few sections, damage boosting may be a good option if a player is bad at multitasking.