Ocean Octorok

Ocean Octoroks are a type of Octorok. As their name suggests, they are solely found in the sea. They are based off the sea-living iteration of Octoroks from The Legend of Zelda: The Wind Waker, though are in games where normal Octoroks are land-based. Like the versions from The Wind Waker, they are quite large, appearing at a comparable size to the player's vehicle.

The Legend of Zelda: Phantom Hourglass
In The Legend of Zelda: Phantom Hourglass, Ocean Octoroks are an enemy in the segments aboard Linebeck's ship, appearing in the northwestern and southeastern quadrants of the map, as well as the southwestern quadrant in the area west of the huge line of rocks. They have a pink body and a yellow shell on their back with a purple swirl design on it. They surface before slowly circling the ship, occasionally submerging to be safe from the cannon. If left alone for long enough, they will attack the ship by ramming it.

The Legend of Zelda: Spirit Tracks
In The Legend of Zelda: Spirit Tracks, Ocean Octoroks are limited to the Ocean Realm, where they are only found in the underwater series of tracks. This time, they have an orange body and tend to move in a circular pattern due to no longer being limited to horizontal movement.