The Boss Kettle for this mission can be found directly in the middle of Suction-Cup Lookout, under the kettle for mission #8 Spinning Campground.
Gameplay
Boss Appearance
Walkthrough
In order to defeat the Octo Samurai, you must splat it to make it drop its Splat Roller on the ground.
The roller grows into a larger form and a tentacle pops out of it. Attack the tentacle 3 times and you win.
Phase 1
The boss will fling its Splat Roller in a similar fashion to inklings, but has a very wide range.
The Samurai can also get on top of his weapon and charge towards the player, leaving behind a wide trail of ink. If he gets a direct his, its an instant Splat. The boss takes a break every time he does this, letting the player get in free hits. He always does a backward jump before doing his charge attack.