The 10 Weirdest Octopuses In The Ocean

The ocean depths hide some truly bizarre creatures, but few can match the sheer weirdness of certain octopus species. These eight-armed weirdos have evolved some mind-blowing adaptations, from arms that detach during sex to deadly venom that can drop a human in minutes. Their brainpower, strange bodies, and downright surprising behaviors make them some of the most fascinating creatures under the sea. Let’s dive into the world of these otherworldly cephalopods that can mimic other animals, build underwater shelters, and generally make you wonder what else is lurking down there.

Related: 10 Freaky Facts And Feats Involving Octopuses

10Argonaut Octopus (Paper Nautilus)

Talk about relationship issues! The argonaut is often called the “world’s weirdest octopus” for good reason. Female argonauts craft a paper-thin, spiral “shell” that isn’t actually a shell at all, it’s an egg case. This delicate calcium carbonate structure doubles as a baby carrier and a built-in flotation device since females naturally sink without it. The size difference between males and females is jaw-dropping, females can grow up to 12 inches long, while the guys barely reach ¾ of an inch. But here’s where it gets truly bizarre: during mating, the male’s specialized reproductive arm (called a hectocotylus) breaks off inside the female and keeps moving around independently. Early scientists who discovered these detached arms actually thought they were parasitic worms.

9Mimic Octopus

If there was an Oscar for underwater impersonations, the mimic octopus would win hands down. This master of disguise can imitate at least 15 different marine animals by changing not just its color and texture, but its entire body shape and how it moves. Feeling threatened? No problem, it’ll transform into a venomous sea snake, spiky lionfish, or other dangerous creatures that predators want nothing to do with. These eight-armed actors prefer hanging out in murky Indo-Pacific waters, using their incredible shapeshifting talents both for defense and when hunting worms and crustaceans. No other cephalopod even comes close to this level of mimicry, it’s like having a whole underwater costume department packed into one body.

8Blue-Ringed Octopus

Don’t be fooled by its adorable size and flashy blue bling, this tiny terror is one of the deadliest creatures in the ocean. Usually just 5 to 8 inches long, the blue-ringed octopus sports about 60 electric-blue rings that light up like neon signs when it feels threatened. Its venom packs a punch of tetrodotoxin, a nasty neurotoxin with zero known antidotes that can leave you completely paralyzed within minutes. One little octopus carries enough venom to kill up to 26 full-grown humans, though thankfully deaths are pretty rare, with around eleven recorded fatalities. Female blue-rings are very maternal, carrying their eggs around “handbag” style instead of hiding them in dens like most octopuses do. They’re often juggling up to 50 eggs at once, talk about multitasking.

7Dumbo Octopus

Remember that flying elephant from Disney? That’s exactly who this deep-sea cutie is named after, thanks to the ear-like fins sticking out from its head. These adorable ocean oddballs live in the crushing depths, we’re talking up to 13,000 feet down, making them some of the deepest-dwelling octopuses around. Unlike their cousins who shoot through the water by forcing it through their siphons, Dumbo octopuses gently flap those ear-fins to cruise around the deep sea. Scientists recently discovered that baby Dumbos hatch with these fins already formed and ready to go. The Grimpoteuthis genus actually includes 15 different Dumbo species, and they mostly munch on bristle worms, copepods, and other tiny critters found near deep-sea vents. Even in the darkest corners of the ocean, evolution has cooked up some seriously unique creatures.

6Coconut Octopus

Who needs a toolbox when you’ve got eight arms and a big brain? The coconut octopus proves that you don’t need a backbone to be clever. These smart little cephalopods collect discarded coconut shells and husks from the seafloor and use them as portable shelters. Even crazier, they’ve been spotted walking on just two arms while carrying their makeshift homes, behavior that scientists consider one of the first solid examples of tool use in invertebrates. Native to tropical waters in the Pacific and Indian Oceans, female coconut octopuses can pop out up to 100,000 eggs in a single clutch. What’s really impressive is how they can manipulate objects way bigger than themselves just to stay safe. It’s pretty compelling evidence that you don’t need to be a mammal to have some serious smarts.

5Blanket Octopus

Talk about relationship inequality. The blanket octopus shows one of the most extreme size differences between sexes in the entire animal kingdom. Females are spectacular creatures stretching 6-7 feet long, while males are tiny little things at just 1.5 inches, making some females roughly 40,000 times heavier than their pint-sized partners. They get their name from the stunning, see-through webbing connecting the arms of females, which looks like a flowing blanket or fancy gown. They can unfurl this tissue to seem way bigger to would-be predators and can even detach it completely as a diversion when things get dicey. Perhaps their coolest party trick? They’re immune to Portuguese man-o’-war stings and have been caught stealing tentacles from these venomous jellies to use as weapons against their own enemies.

4Ghost Octopus

The ghost octopus is the new kid on the block, NOAA researchers only recently spotted this spooky cephalopod near Hawaii. With its pale, almost see-through body and eerie movements in the deep ocean darkness, the name pretty much chose itself. This ghostly creature hangs out in the pitch-black depths where sunlight is just a distant rumor. Like many octopus moms, female ghost octopuses wrap themselves around their egg clutches for protection, but what sets them apart is their extreme dedication, they guard those eggs for years without eating a single bite, eventually dying as their babies hatch. This extreme maternal devotion ensures their offspring survive, highlighting just how complex these boneless wonders really are.

3Star-Sucker Pygmy Octopus

If you’ve ever wondered what the world’s tiniest octopus looks like, meet the star-sucker pygmy. This little guy measures less than an inch long and weighs less than a paperclip, making it one of the smallest known octopus species [1]. Despite being easy to miss in its Pacific Ocean habitat, this miniature marvel punches well above its weight class. What’s wild is that this tiny creature has the same complex nervous system and problem-solving skills as its giant relatives, just packed into a body smaller than your thumb. Its diminutive size lets it hide in the tiniest nooks and crannies that bigger predators can’t even think about squeezing into. Sometimes in evolution, going smaller rather than bigger is the winning ticket.

2Dorado Octopus

Discovered in 2023 off the coast of Costa Rica, the Dorado Octopus is part of the Muusoctopus genus and has some interesting traits. This species has small eyes, a robust body, and short arms with double-row suckers. What really stands out is its ability to brood its eggs near hydrothermal springs, using the warm vent fluids to speed up incubation. Unlike most deep-sea octopuses that prefer cooler waters, this one thrives in what might be one of the planet’s toughest environments. Living next to underwater volcanic vents where temperatures swing wildly and chemicals abound, this octopus is a true survivor. Scientists are fascinated by how it adapts to these conditions, as it could offer insights into how life might thrive in harsh environments.

1Hairy Octopus

The Hairy Octopus, found in the waters around Indonesia and recently spotted in Okinawa, Japan, is a tiny marvel. At just 2 inches long, it uses thin skin flaps that look like hair to blend into its surroundings, mimicking seaweed or algae. Its color-changing abilities, from white to red or brown, add to its camouflage skills. This elusive cephalopod inhabits areas with rubble and seagrass at depths of 26 to 65 feet. Though its diet and lifespan remain a mystery, divers who spot this octopus count it as a highlight of their underwater adventures.

fact checked by
Alex Alvarez