H8ERS GONNA H8
Hatchan The Octopus (蛸の八ちゃん, "Tako no Hatchan") is a Japanese comic about an octopus, Hatchan, who goes on land to learn about being human and has various misadventures. The author, Suihō Tagawa (田河水泡), is more famous for his Norakuro character, a semi-autobiographical, anthropomorphic dog soldier in a thinly veiled Japanese Imperial Army.
The comic was originally serialized in the 1930s in the weekly magazine 婦人子供報知 ("Women Children Alarm" according to ever-helpful Google) and later compiled in a book. The Japanese National Diet Library has full scans of the 1949 and 1951 editions. There was also a deluxe fully colored edition published in 1969. (WorldCat lists the title of the 1969 and 1935 editions as "蛸の八ちゃんの上陸", which translates as "The Landing/Landfall of Hatchan The Octopus".)
There's not really a lot online about this comic in Japanese, much less English. It was once popular enough to spawn merchandise, but now seems mainly remembered by old folks.
The name Hatchan could be translated into English as Lil' Eight. "八ちゃん" in full is "Hachi-chan", which is contracted to "Hatchan" (at least in the few sources I've found that Romanize it). "八" (hachi) is "eight" and "ちゃん" (-chan) is the diminutive honorific. That his name in English sounds like it has something to do with his stylin' nautical cap is, I assume, pure lucky coincidence.
The plot, as best I can make out (I probably have much of this completely wrong): Hatchan wishes he was reincarnated as a human because being an octopus is boring. He gets himself caught in a bucket by a friendly human (who is Suihō Tagawa), who takes him home and gives him a suit, which he wears with two limbs in each sleeve and pant leg. He then goes into town and tries to find work and start his new human life. Things don't go his way, but he still makes enough to buy a captain's hat and glasses from a street vendor. Eventually he learns that humans will pay top yen for branches of coral, so he enlists a bunch of young octopuses to gather as much coral as they can. He sells it all and gets literally bundles of cash.
Hatchan uses his wealth to buy little sailor suits (or school uniforms) for his horde of octopus minions (or are they his children?) who join him on land, along with his two gakuran-wearing lieutenants, lumpy-headed Kinchaku (きんちゃく, a type of draw-string purse) and pointy-headed Billiken (ビリケン, named after an American charm doll that became weirdly popular in Japan). He teaches the octopuses to read Japanese then buys himself a house.
They settle into some sort of domestic life interspersed with wacky antics involving dog attacks, doctor bills, sharp knives, and presumably-existential monologues I can't read. The end.
The way Hatchan wears his suit, fumbles about in the human world, and makes a home on land is like a precursor to Octodad from the eponymous game series. The comic is also reminiscent of Osaru no Kantai (The Monkey Fleet), not only for the traditional Japanese depiction of octopuses with anatomically-inaccurate "O" mouths, but also the whole octopus-hordes-coming-ashore theme. However, unlike those melon thieves or the horde in my previous post, this octopus horde appears bent only on economic conquest (even if they are militantly dressed).