Octoplus

The Octoplus is a treasure in. It is a tako sausage, or octopus sausage, styled like an octopus.

Blossoming Arcadia
There is an Octoplus inside of a Waddlequaff at the northernmost section of the area. To collect this treasure, you must either defeat the Waddlequaff and throw 2 Pikmin at it, or throw 2 Pikmin when the Waddlequaff spits it out, and distract it while the treasure is being carried off.

Seafloor Resort
There are two Octopli on the absolute northwest of sublevel 2 of the Seafloor Resort, beyond the water, on the edge of the surrounding tank. To collect them, you must throw 2 Pikmin at each one.

Frozen Inferno
There is an Octoplus lying on the ground at the far west side of sublevel 1 of the Frozen Inferno next to a Heroic Sword. To collect this treasure, you must throw a fire starter at the bundles of straw in front of it, or hope a Pyroclasmic Slooch ignites them. Then, throw 2 Pikmin at it.