Buzz
Imagine you’re a film producer, and someone pitches a story about a tentacled alien with the ability to shapeshift, turn invisible, and shoot a dazzling cloud of chemicals at its foes. You’d probably respond with a sigh and say, “No, that’s just an octopus.” It’s easy to forget that countless bizarre creatures like this exist in our oceans; at some point, science decided to let pure, nightmarish curiosity take the wheel. But even among the weirdest of the world’s creatures, there are still the truly extreme cases.
10. Atolla Jellyfish
Atolla jellyfish are fairly common across the globe’s oceans, though they’re not something you’ll find near the shore. These creatures prefer depths of over 700 meters (2,200 feet) below the surface. Like many of their deep-sea relatives, they possess bioluminescence, glowing like fireflies in the dark. But unlike anglerfish, which use their glowing lights to lure prey, atollas use their bioluminescence as a defense mechanism. When threatened, they emit a rapid series of bright flashes, much like a strobe light. This dazzling display attracts even larger predators, who target the creature that’s threatening the atolla, giving it a chance to escape.
The atolla jellyfish also features a single, long tentacle, which it uses to capture its prey. With the tip of this tentacle, it ensnares its victim and drags it through the water, jerking it back and forth until the creature tires out—much like a fisherman reeling in a big catch.
9. Antarctic Ice Fish
Extremophiles, animals that thrive in extreme environments, are generally pretty out of the ordinary. But the Antarctic ice fish might just be the most bizarre. True to its name, this fish lives in the cold waters around Antarctica, typically in temperatures below freezing and at depths that can reach up to a kilometer (about 3,300 feet).
This fish is completely transparent—its blood included. While it still has blood, it lacks hemoglobin, the protein in red blood cells that carries oxygen and gives blood its color. It’s the only vertebrate known to have this trait, and scientists are still trying to figure out why the ice fish evolved this way. On top of that, its blood contains an antifreeze protein, which stops its blood and soft tissues from freezing, allowing it to survive in sub-zero waters without turning into a frozen fish popsicle.
8. Emperor Shrimp
The tiny, brightly colored emperor shrimp almost looks like a candy rather than a living creature, but its vibrant hue serves an important purpose... although, truth be told, no one knows exactly why they're so colorful, even though they've been studied since 1967. One possibility is that they don’t need camouflage. These shrimp almost always live on the backs of a specific species of sea slug, the nudibranch known as Hexabranchus marginatus, which has few natural predators due to the toxins it absorbs from its diet. Since there’s not much out there that could threaten them, maybe the emperor shrimp is just showing off its bold colors.
7. Blue Dragon Sea Slug
Most animals hunt creatures smaller than themselves—it's just how nature operates. But the blue dragon? It scoffs at logic and targets the biggest, most dangerous animals it can find, like the Portuguese man o’ war, and if that’s unavailable, it’ll go after other blue dragons. By feeding on the tentacles of the man o’ war, blue dragons absorb the venomous cnidocyte cells, which they then store in sacs in their bodies to use as a defense mechanism when threatened.
But the oddities don’t end there. While most sea slugs crawl along the ocean floor, blue dragons take a different approach. They swallow an air bubble and float just beneath the water’s surface. Seen from below, they resemble a spider walking on a mirror. They drift with the current, eating anything that crosses their path.
6. Felimare Picta
The Felimare picta is a species of sea slug found in warm, subtropical waters, particularly around the Mediterranean Sea and the Gulf of Mexico. There are six distinct subspecies of Hypselodoris, and they belong to the nudibranch family of sea slugs—each one more utterly bizarre than the last.
Nudibranchs are relatively small, typically growing to around 20 centimeters (8 inches), although a few have been recorded at lengths surpassing 64 centimeters (25 inches). As mollusks (like snails), they don't rely on shells for protection. Instead, they have a few remarkable tricks up their vibrant sleeves—such as sweating acid. If that doesn’t scream Alien, we’re not sure what does.
5. Gorgonian Wrapper
The Indo-Pacific region boasts some of the most diverse marine life on Earth, including the gorgonian wrapper. This creature is a type of sea anemone, which means—yes—it’s a predator. And it's as merciless as it appears. Gorgonian wrappers, like other anemones, produce cnidocytes—cells that work like tiny, toxic shrapnel grenades. These cells line the tentacles, and when a fish brushes against them, a trigger activates, causing the cell to explode, shooting paralyzing harpoons into the fish.
The process that launches the anemone’s venom is one of the quickest reactions in the animal kingdom. It takes less than 700 nanoseconds for the cnidocyte to fire its deadly payload (just to give you an idea, a nanosecond is one-billionth of a second).
4. Wonderpus
With one of the most fitting Latin names in the animal kingdom, Wunderpus photogenicus is a rare predatory octopus native to the Philippines. The name comes from their photogenic nature—people love to take pictures of them. But while kittens may be photogenic, the wonderpus is far from cute and cuddly. These crepuscular hunters (active at dawn and dusk) stalk their prey by creeping along the ocean floor on long, flattened tentacles. When they need to hide, their vivid coloring fades to match the surrounding sand and coral. However, if threatened, they suddenly burst into a violent blaze of red and orange, signaling danger to predators.
Like most octopuses, wonderpuses are incredibly intelligent. This video showcases a wonderpus constructing a wall of coral to conceal itself. Despite only being discovered in 2006, we’re learning more about these fascinating creatures every day. They’ve made things easier for researchers—the unique white spot patterns on their backs are like fingerprints, one of a kind for each individual.
3. Bobbit Worm
Nothing about the bobbit worm is pleasant or appealing. Even its name has morbid origins, stemming from a 1993 court case involving Lorena Bobbitt, a knife, and... well, something that looks like a worm. Equal parts Tremors Graboid and monstrous nightmare, the bobbit worm can stretch up to three meters (10 ft) long. It burrows into the ocean floor, with only a small portion of its body exposed. When a fish swims by, the worm lunges forward, grabs the fish with its enormous pincers, and pulls it underground to devour it.
Most of these creatures are not found in the open ocean, but instead often hitch a ride in saltwater aquariums. They sneak into the tanks via rocks and gravel taken from the sea, and grow undetected. In 2009, a giant bobbit worm was discovered in the Blue Reef Aquarium in England. It was uncovered when staff were investigating why all the fish had mysteriously disappeared.
2. Giant Siphonophore
At first glance, this creature doesn’t seem like much, but when you consider its size, the giant siphonophore becomes awe-inspiring. These deep-sea dwellers can grow over 40 meters (130 ft) in length—imagine the height of a 13-story building or even longer than a blue whale, the largest vertebrate on Earth.
However, the giant siphonophore isn’t exactly one creature; it’s actually a colony made up of millions of individual beings known as zooids. Each group of zooids has a specific role: some hunt for food, others digest it, and some are dedicated to protecting the colony. Together, they function as one unit, much like a country—or more fittingly, a group of midgets in an overcoat.
Living so deep in the ocean (about a kilometer, or half a mile down), siphonophores face intense pressure—half a ton per square centimeter. This immense pressure makes them challenging to study, and if they’re brought up too quickly, they burst like balloons due to the rapid decrease in pressure.
1. Lionfish
Lionfish are one of the most well-known types of fish, with 10 species in total. They are undeniably stunning yet dangerously venomous, native to the Indian Ocean and southern Pacific. However, two species were introduced to the East Coast of North America in the 1990s, and this has led to significant problems. They reproduce at an alarming rate, like underwater rabbits, and have no natural enemies to keep their numbers in check.
The lionfish population boom has gotten so out of hand that researchers in Honduras are now attempting to train sharks to prey on them. Normally, sharks avoid lionfish altogether. The only real threat to these predators is, ironically, their own kind: when food is scarce, lionfish resort to cannibalism and start eating each other.
