"Modeled after the Ultimate Octobot. But where did they manage to find an Ultimate Octobot?"
Battle Memory

Return of Octobot is an enemy in Mother 3. It is found on the Laboratory Level of the Empire Porky Building and is modeled after the Ultimate Octobot; the only major differences are their colors and overworld sprite. The Return of Octobot retains the Ultimate Octobot's ability to attack and steal food. Even though it is modeled after the Ultimate Octobot, it isn't as powerful.

His battle sound is Battle Sound 3 which falls under Code Numbers 445 for regular attack, 446 for Smaaaash! and 447 for Miss. However, because he never uses regular attacks that play a battle sound on his own, Kumatora must use Brainshock on it to get it to use a regular attack.