10 Weirdest Octopuses: Experts of Disguise, Deception, and Downright Bizarre Behavior

The ocean is a realm of endless wonder, teeming with creatures so alien they seem plucked from science fiction. Among the most fascinating and enigmatic inhabitants are the octopuses. These intelligent, boneless invertebrates have captivated scientists and storytellers for millennia with their problem-solving skills, camouflage abilities, and sheer strangeness. But while all octopuses are remarkable, some species take "weird" to an entirely new level. From deep-sea dwellers with floppy ears to brilliant mimics that impersonate other animals, the ocean hides octopuses that defy imagination.

In this deep dive, we’ll explore **the 10 weirdest octopuses in the ocean**, uncovering the bizarre adaptations, behaviors, and appearances that make them true outliers in the cephalopod world. Prepare to have your perception of marine life forever altered!

Why Octopuses Are Nature’s Ultimate Oddballs

Before we plunge into the depths to meet our contenders, let’s appreciate *why* octopuses are such a hotbed for weirdness:

• Radical Body Plan: Lacking bones, an octopus can squeeze through openings barely larger than its beak. Their eight arms, lined with hundreds of suckers (each with its own "taste and touch" sensors), operate with incredible autonomy.
• Camouflage Experts: Their skin contains specialized cells called chromatophores, leucophores, and iridophores, allowing them to change color, pattern, and even skin texture in milliseconds to vanish into their surroundings.
• Intelligence Beyond Compare: Octopuses exhibit complex problem-solving, tool use, play behavior, and even distinct personalities – all packed into a distributed nervous system where two-thirds of their neurons reside in their arms!
• Short, Intense Lives: Most live only 1-3 years, evolving rapidly and packing an astonishing amount of biological and behavioral innovation into a brief lifespan.

This potent combination of anatomy, physiology, and intelligence creates the perfect storm for evolutionary experimentation, resulting in the truly bizarre species we’re about to meet.

1. The Dumbo Octopus (Grimpoteuthis spp.): The Deep-Sea Disney Character

Weirdness Factor: Looks like a flying elephant with ear-like fins, lives in the crushing abyss.

Imagine plunging thousands of meters below the sunlit surface, into the perpetual darkness and crushing pressure of the abyssal plain. Here, drifting just above the seafloor, you might encounter the utterly charming Dumbo Octopus. Named after Disney’s famous elephant, this creature possesses two large, ear-like fins protruding from the top of its mantle (head). These fins aren’t for hearing; they flap gracefully, propelling the octopus through the water with an eerie, otherworldly elegance, resembling a slow-motion underwater flight.

• Habitat: Found at extreme depths, typically 3,000 to 4,000 meters (sometimes deeper!), making them one of the deepest-living octopus genera.
• Appearance: Soft, gelatinous body, often pale pink, purple, or brown. The "ears" (fins) are its most defining feature. Its eyes are relatively large but adapted for near-total darkness.
• Behavior: Unlike many octopuses, Dumbo Octopuses don’t crawl much. They primarily drift and hover, using their fins and arm movements for navigation. They swallow prey whole, including small crustaceans and worms found on the deep-sea floor.
• Why So Weird? Living in the deep ocean’s energy-poor environment favors energy-efficient movement. Flapping fins require less effort than jet propulsion or crawling. Their gelatinous consistency helps them withstand immense pressure without needing heavy shells or bones. They are a perfect example of adaptation to one of Earth’s most extreme habitats.

2. The Coconut Octopus (Amphioctopus marginatus): The Mobile Homebuilder

Weirdness Factor: Carries coconut shells and clam shells as portable armor, exhibiting tool use.

Tool use was once considered a hallmark of primates and a few birds. Enter the Coconut Octopus, a humble cephalopod that turns this notion on its head (or mantle). This remarkably clever octopus, found in tropical waters of the Indo-Pacific, has a unique solution to the dangers of life on a sandy, exposed seabed: it builds and carries its own portable shelter.

• Habitat: Shallow, sandy or muddy bottoms, often near coral reefs, in the Indo-Pacific.
• Appearance: Typical octopus shape, usually brownish with distinctive white spots or lines on its arms. Reaches about 15-20 cm in mantle length.
• Behavior: This is where the weirdness shines. The Coconut Octopus actively seeks out discarded coconut halves or large clam shells. It meticulously cleans them out, then stacks them together, creating a spherical fortress. It then carries this cumbersome structure underneath its body, walking awkwardly on its arm tips like a stilt-walker carrying a heavy load. When threatened, it quickly pulls the shells closed around itself, vanishing inside. It’s a stunning display of foresight, planning, and tool manipulation.
• Why So Weird? This behavior provides crucial protection in an environment lacking natural crevices. It requires significant cognitive ability: recognizing useful objects, transporting them (despite the energy cost), and assembling them for future use. It challenges our understanding of invertebrate intelligence and tool use.

3. The Blue-Ringed Octopus (Hapalochlaena spp.): The Tiny, Glowing Terror

Weirdness Factor: Beautifully patterned, smaller than a golf ball, but packs one of the ocean’s most potent venoms.

Don’t let its diminutive size and stunning appearance fool you. The Blue-Ringed Octopus is arguably one of the most dangerous animals in the sea. Found in tide pools and coral reefs across the Pacific and Indian Oceans, this tiny octopus (often smaller than 15 cm including arms) is adorned with vibrant blue rings that seem to glow or pulsate when the animal feels threatened.

• Habitat: Shallow reefs, tide pools, rocky areas, and sandy bottoms in warm coastal waters.
• Appearance: Pale yellow or brown skin covered in iridescent blue rings (typically 50-60 rings). The rings are normally faint but become intensely bright blue as a warning display when disturbed.
• Behavior: Generally shy and reclusive, preferring to hide in crevices or under rocks during the day. They hunt small crabs and shrimp. Their venom, tetrodotoxin (the same potent neurotoxin found in pufferfish), is produced by bacteria in their salivary glands. A single bite delivers enough venom to paralyze and kill an adult human within minutes, with no known antivenom. Crucially, the bite is often painless, making it even more insidious.
• Why So Weird? The combination of extreme toxicity packaged in a small, visually striking body is a powerful evolutionary strategy. The bright blue rings serve as an unambiguous warning to potential predators (and humans!) – "I am deadly, back off!" It’s a classic example of aposematism (warning coloration) taken to a lethal extreme.

4. The Mimic Octopus (Thaumoctopus mimicus): The Ultimate Impersonator

Weirdness Factor: Can dynamically impersonate at least 15 different marine animals with uncanny accuracy.

If the Coconut Octopus is a clever tool user, the Mimic Octopus is the ultimate con artist of the sea. Discovered only in 1998 off the coast of Indonesia, this medium-sized octopus (up to 60 cm arm span) possesses an almost unbelievable ability: it doesn’t just blend into the background; it actively impersonates other, often more dangerous, sea creatures.

• Habitat: Shallow, murky estuaries and bays with sandy or muddy bottoms in the Indo-Pacific.
• Appearance: Light brown or beige base color with distinctive white and brown stripes running along its arms and mantle. Relatively long, thin arms.
• Behavior: This is its superpower. When threatened or hunting, the Mimic Octopus contorts its body and changes its color and texture to mimic specific animals:
•     Lionfish: Spreads its arms wide, trailing them like venomous spines.
•     Flatfish: Flattens its entire body against the seafloor, swimming with a undulating motion.
•     Sea Snake: Hides in a hole, leaving only two arms protruding, waving them like a banded sea snake.
•     Jellyfish: Pulses its mantle and arms upwards, trailing them like stinging tentacles.
•     And more: Stingrays, crabs, brittle stars, even giant crabs! It chooses its mimic based on the perceived threat.
• Why So Weird? This dynamic, context-dependent mimicry is unparalleled in the animal kingdom. It requires not only incredible physical control over its body but also sophisticated cognitive processing to recognize threats, select an appropriate model, and execute the impersonation convincingly. It’s a survival strategy that leverages the fear other animals have for venomous or unpalatable species.

5. The Flapjack Octopus (Opisthoteuthis californiana): The Deep-Sea Pancake

Weirdness Factor: Looks like a flattened, gelatinous pancake with stubby arms.

Living at moderate depths (200-1,000 meters) off the Pacific coast of North America, the Flapjack Octopus is a creature of comical proportions. Its body is incredibly flattened, resembling a pancake or a flattened mushroom cap. Its arms are short and stubby compared to most octopuses, connected by a deep webbing, giving it an overall appearance that is both adorable and utterly bizarre.

• Habitat: Continental slope and shelf waters, often near the seafloor.
• Appearance: Pale pink, orange, or reddish-purple. The mantle is extremely flattened (hence "flapjack"), and the arms are short with extensive webbing. Eyes are large and prominent.
• Behavior: Moves slowly, often hovering just above the bottom. It uses a combination of fin flaps (like the Dumbo, but smaller) and pulsing of its web to swim. It feeds on small crustaceans and worms. Its gelatinous body helps maintain buoyancy at depth.
• Why So Weird? The flattened shape and webbed arms are adaptations for life in the deep sea. This body plan increases surface area relative to volume, potentially aiding in buoyancy control and reducing energy expenditure for movement. It’s a shape optimized for drifting in the quiet, dark waters of the mesopelagic zone.

6. The Blanket Octopus (Tremoctopus spp.): The Draping Diva with Extreme Size Differences

Weirdness Factor: Females have enormous, flowing cape-like webs; males are tiny and dwarfed by females.

The Blanket Octopus is a study in dramatic contrasts, particularly between the sexes. The female is a spectacular sight: she can grow up to 2 meters *in length* (including the blanket), with four of her arms elongated and connected by vast sheets of iridescent webbing that trail behind her like a flowing cape or blanket. This "blanket" can be unfurled dramatically when threatened, making her appear much larger to predators. The male, however, is a minuscule counterpart, measuring only about 2-4 centimeters – roughly the size of a walnut. He lacks the blanket entirely.

• Habitat: Open ocean (pelagic) in tropical and subtropical waters worldwide.
• Appearance:
•     Female: Large, with four long arms bearing the extensive, colorful (often red, blue, or iridescent) webbing. The other four arms are shorter. Body is gelatinous.
•     Male: Tiny, lacks the blanket webbing, has a modified arm (hectocotylus) for reproduction.
• Behavior: Females drift in the open ocean, trailing their blanket. They are immune to the stings of Portuguese Man o' War, whose tentacles they have been observed tearing off and wielding as defensive weapons! Males spend their short lives searching for a mate. Upon finding one, the male detaches his specialized arm (containing sperm packets) and presents it to the female, who stores it for later fertilization. The male then dies. This is one of the most extreme examples of sexual dimorphism (size difference between sexes) in the animal kingdom.
• Why So Weird? The female’s blanket is a brilliant anti-predator display in the featureless open ocean. The male’s tiny size is likely an adaptation to the vastness of the pelagic environment – being small makes finding a mate (which is rare) easier and requires fewer resources. The detachable arm ensures reproduction even if the male is eaten immediately after mating.

7. The Glass Octopus (Vitreledonella richardi): The See-Through Specter

Weirdness Factor: Nearly transparent body allows you to see its internal organs, including its optic nerve.

Imagine an octopus so transparent it looks like a living glass sculpture. The Glass Octopus, inhabiting the mesopelagic to bathypelagic zones (200-1,000+ meters deep), achieves this remarkable feat. Its entire body, including its mantle, head, and arms, is almost completely translucent. This isn’t just for show; it’s a highly effective form of camouflage in the dimly lit deep sea, where shadows are often the only giveaway.

• Habitat: Deep, open ocean waters worldwide, typically below 200 meters.
• Appearance: Ghostly transparent. You can clearly see its internal organs: a tubular, U-shaped digestive gland running the length of its mantle, its eyes (which are cylindrical and point upwards, possibly to detect silhouettes of prey above), and even the optic nerve connecting the eye to the brain! Only its eyes and a few internal structures are opaque.
• Behavior: Little is known due to its deep-sea habitat and transparency, making it difficult to study. It’s believed to hover vertically in the water column, feeding on small crustaceans like copepods. Its transparency is its primary defense.
• Why So Weird? Transparency is the ultimate camouflage in the deep ocean’s twilight zone, where light filters down from above. By minimizing the scattering and absorption of light, the Glass Octopus becomes nearly invisible to predators looking up from below or down from above. Seeing its internal organs is a bizarre side effect of this survival strategy, offering scientists a unique window into cephalopod anatomy.

8. The Seven-Arm Octopus (Haliphron atlanticus): The Giant with a Hidden Arm

Weirdness Factor: One of the largest octopuses, but males have a coiled, sac-like arm hidden in a pouch, making it appear to have only seven arms.

Don’t let the name fool you – the Seven-Arm Octopus *does* have eight arms. The confusion arises from the male’s unique reproductive anatomy. This deep-sea dweller is one of the largest known octopus species, with females potentially reaching lengths of over 4 meters and weights exceeding 75 kg. The males, while smaller, possess a bizarre modification: their third right arm (the hectocotylus) is highly specialized for reproduction. It’s coiled within a protective pouch near the left eye and is often not visible, leading to the mistaken impression of only seven arms.

• Habitat: Deep ocean waters worldwide, often at depths exceeding 1,000 meters.
• Appearance: Large, robust body. Males: The modified hectocotylus arm is coiled and hidden in a pouch. Females: Have eight normal-looking arms. Color is often reddish or purplish.
• Behavior: Solitary deep-sea predators, feeding on fish and other cephalopods. Males use their specialized arm to transfer sperm packets to the female. The arm can detach and remain inside the female’s mantle cavity. Little is known about their daily lives due to the depth and rarity of sightings.
• Why So Weird? The hidden hectocotylus is an extreme adaptation for deep-sea reproduction. Protecting this vital reproductive structure within a pouch likely prevents damage during the male’s search for a mate in the vast, dark abyss. Their large size is unusual for deep-sea octopuses, which tend to be smaller and more gelatinous.

9. The Star-Sucker Pygmy Octopus (Octopus wolfi): The Miniature Marvel with Starry Suckers

Weirdness Factor: One of the smallest octopuses in the world, with suckers shaped like tiny stars.

Size isn’t everything, and the Star-Sucker Pygmy Octopus proves that weirdness comes in tiny packages. This diminutive creature holds the title for the world’s smallest known octopus species, with adults often measuring less than 2.5 cm (1 inch) in mantle length and weighing less than a gram. But its minuscule size isn’t its only claim to fame. Look closely (very closely!), and you’ll see that its suckers aren’t the typical round discs. Instead, they are shaped like tiny, perfect stars.

• Habitat: Shallow, warm waters of the Indo-Pacific, often found in coral rubble or seagrass beds.
• Appearance: Tiny! Pale brown or beige coloration. The defining feature is the star-shaped suckers visible under magnification.
• Behavior: Lives a cryptic life, hiding in small crevices or within debris. Feeds on tiny crustaceans. Its small size makes it extremely vulnerable, so it relies heavily on camouflage and hiding.
• Why So Weird? The star-shaped suckers are a unique morphological feature, though their exact functional advantage (if any) over round suckers in such a small animal isn’t fully understood. Its incredibly small size pushes the limits of how complex an organ system (including a highly developed brain and nervous system) can be packed into such a minuscule body. It represents the extreme miniaturization end of the octopus spectrum.

10. The Argonaut (Argonauta argo): The Shell-Building Surface Drifter

Weirdness Factor: Females secrete and inhabit a beautiful, paper-thin, spiral shell; males are tiny and shell-less.

The Argonaut, or Paper Nautilus, isn’t a true nautilus (which has a chambered shell and is a different cephalopod group). It’s an octopus, but one with a shell-building secret that sets it apart. Only the female Argonaut constructs a shell. She secretes a delicate, calcareous, spiral shell using two specialized arms that are greatly expanded and fused together. This shell isn’t attached to her body; she lives inside it, much like a hermit crab, but she built it herself! Males are dwarfed (only about 1-2 cm), shell-less, and die soon after mating.

• Habitat: Open ocean (pelagic) in tropical and subtropical waters worldwide, often near the surface.
• Appearance:
•     Female: Resembles a small, delicate nautilus shell (up to 30 cm diameter), often with beautiful ridges and patterns. The animal inside has a typical octopus head and eight arms, with two highly modified for shell secretion.
•     Male: Tiny, without a shell, with a specialized hectocotylus arm for reproduction.
• Behavior: Females drift near the surface, trapped air within their shells for buoyancy control. They feed on plankton and small fish. Males locate females and use their detachable hectocotylus to transfer sperm. The female uses the shell not just for protection but also as a brood chamber for her eggs.
• Why So Weird? The female’s ability to secrete a complex, external shell is unique among octopuses. It’s an evolutionary convergence with true nautiluses and shelled gastropods, but achieved through a completely different biological mechanism (secreted by arms, not the mantle). The shell provides buoyancy and protection in the open ocean. The extreme sexual dimorphism and the male’s detachable reproductive arm mirror strategies seen in the Blanket Octopus.

Conclusion: The Ocean’s Endless Octopus Oddities

From the floppy-eared Dumbo drifting in the abyss to the brilliant mimic con artist on the sandy flats, from the tiny, star-suckered pygmy to the giant, seven-armed (well, eight-armed really) deep-sea behemoth, the world of octopuses is a treasure trove of evolutionary weirdness. These 10 species represent just a glimpse into the astonishing diversity and adaptability of these intelligent cephalopods.

Their strangeness isn’t just for show; it’s a testament to the power of evolution. Each bizarre feature – the transparent skin, the portable coconut shelter, the venomous bite, the flowing cape, the star-shaped suckers – is a finely honed solution to the unique challenges of their specific niche, whether it’s the crushing pressure of the deep sea, the featureless expanse of the open ocean, or the dangerous predator-filled shallows.

Studying these weird octopuses does more than satisfy our curiosity about the odd. It pushes the boundaries of our understanding of intelligence, camouflage, tool use, reproduction, and the very possibilities of life on Earth. They remind us that the ocean, even in the 21st century, holds countless secrets and creatures so strange they seem like dreams. The next time you gaze at the sea, remember: beneath the waves, an octopus is probably doing something utterly, wonderfully weird. Keep exploring, keep questioning, and never underestimate the octopus’s capacity for surprise!

Want to Dive Deeper?

•  Learn more about octopus intelligence and their remarkable problem-solving abilities.
•  Discover the secrets of cephalopod camouflage and how chromatophores work.
•  Explore the mysteries of the deep sea and the creatures that thrive in perpetual darkness.

The ocean’s weirdest octopuses are waiting to be discovered – what will you find next?