He is an octopus that looks very much like Squidward. He wears a brown shirt with a blue bow and a navy blue hat with a red stripe on it. He also holds a clarinet in his hands.
He appears in "Pull Up a Barrel" as one of the two guards watching Mr. Krabs. Like Squidward, he also plays the clarinet. After, when Mr. Krabs went to the Sick Bay, him along with a few other sailors are there.
While it is not confirmed, this sailor might have not looked like Squidward. Mr. Krabs may have made him look like Squidward to make the story more relatable.