The Spiny Lobster, also known as the Ornate Spiny Lobster (in the second game), is a medium-sized lobster seen in both Endless Ocean games.
"These common creatures have cylindrical bodies that are covered in a hard shell, two antennae, and ten legs. They are blue-green in color with subtle yellow markings on the back. They can be seen year-round, mostly in the Rock Bluff area."
"This hard-shelled animal is the largest in its family,. It has ten legs and two pairs of antennae--one long and this, stretching out in front to sense flavor and odor, and the other heavier and stretched out over its shell that it uses to explore its immediate environs. Its shell is blue-green with a pale yellow pattern on the back.
[Growing by Shedding]
Its eggs hatch and produce phyllosoma larvae, which float freely in the water for a long time/ They molt repeatedly as they grow and eventually become puerulus, where they look like adults except for being transparent, and settle on the seafloor. After molting one more time, they take on their adult coloring, and they continue to molt as they grow larger."
In the second game, solitary examples of this creature are found at coordinates E-1 and C-4. If it is not at one of these locations, it is probably at the other, and it switches back and forth with a Crown-Of-Thorns Starfish.