Get to Know These 8 Mysterious Sea Creatures

From monstrous crabs to goblins of the sea, there are some thrilling ocean dwellers out there. Here are some fascinating facts about some of the most mysterious animals in the sea.

1. Japanese Spider Crab (Macrocheira kaempferi)

A massive crab that looks like a spider. No need to be scared, they usually sit around 1000 feet deep. Spider crabs are the largest of all crustaceans and they can become very old — at least a century, or older! Despite their intimidating look, they are gentle giants and prefer to scavenge dead animals and plants. They belong to a group known as decorator crabs which adorn their shells with sponges or anemones for camouflage.

2. Anglerfish (Lophiiformes)

You might know the Anglerfish from the movie “Finding Nemo.” Anglerfish are known for having a type of “fishing rod” at the top of their head that can light up. The glow in the deep dark waters they inhabit attracts unsuspecting fish which then get gobbled up by the anglerfish’s huge mouth. Male anglerfish don’t have this skill since they latch on to the much larger females with their sharp teeth. Over time he fuses with the female and loses all his organs except the reproductive ones. Unfortunately, this alien-looking fish is endangered because it is seen as a delicacy in certain parts of the world.

3. Blobfish (Psychrolutes marcidus)

This poor fish was voted the ugliest animal in 2013. And not surprisingly, since this This poor fish was voted the ugliest animal in 2013. We think this gelatinous blob with no bones and virtually no muscles is actually pretty cute! When the blob is in its natural habitat — 3000 feet deep — it actually looks pretty normal. It has adapted to the huge amounts of pressure at this depth that holds its shape. Down there in the dark silent waters, the water pressure is 120 times higher than at the surface.

4. Greenland shark (Somniosus microcephalus)

We know very little about this mysterious shark because we rarely see it. It likes to occupy cold arctic waters at around 2000 feet deep. Greenland sharks are one of the largest shark species growing 20 feet long and weighing up to 2,500 pounds. They can also become very old. There is evidence of one shark that is around 512 years old. Some strange things have been found in Greenland sharks’ stomachs, including the remains of polar bears, horses, moose, and in one case an entire reindeer. But no fear, they probably scavenged these animals since they are very blind and super slow. Their meat is poisonous since it contains trimethylamine oxide (a natural antifreeze).

5. Colossal squid (Mesonychoteuthis hamiltoni)

These giants seem like they belong in a sci-fi novel, yet they roam our oceans at depths of around 3000 feet. They are truly colossal; they measure around 32 feet long (the size of a school bus!) and weight 1100 pounds. They are the largest invertebrate we know of (because we don’t know who else lurks in the depths). Their eyes can be 10” in diameter, or the size of a dinner plate. Colossal squids have a beak, a hard structure much like a parrot’s beak that they use to catch fish. They only have one predator: the sperm whale. When these two meet it is truly a real-life clash of the titans. The squid doesn’t go down without a fight and many sperm whales carry the battle scars from their dinner.

6. Black swallower (Chiasmodon niger)

This deep-sea fish can be found in the deep at 9,000 feet (thirty times the length of a football field)! This relatively small fish of around nine inches isn’t spooky because of its size but how it eats. They feed by eating their prey whole, even prey measuring twice their size. They do this with a massive jaw that they can extend to engulf their target. When they get too greedy and take on a fish that is too big, the meal sits in the black swallower’s expandable stomach, releasing gases. This gas floats the black swallower up to the surface, ending in its untimely demise since they are not adapted to the low pressure at the surface.

7. Goblin shark (Mitsukurina owstoni)

The goblin shark is also known as a living fossil because it swam the oceans 125 million years ago. This is when the first primitive mammals had just entered the scene. It is named the goblin shark for obvious reasons, namely the creepy head with protruding sharp teeth. In fact, it has many many teeth: 53 rows at the top and 62 at the bottom. It lives at around 4300 feet deep but has also been spotted at 130 feet at night. It feeds by slingshotting its jaw forward. If we were able to eat like that, we could eat a piece seven feet away from our face. They have a pinkish color because of their translucent skin.

8. Giant Grenadier (Albatrossia pectoralis)

The Giant Grenadier is also known as a rat-tail because of its long thin tail. It can reach 6 feet in length! They have a gaping mouth and light-emitting organs to attract their favorite prey, the vampire squid (named so due to its deep red color and cape-like skin). Grenadiers can become pretty old, estimated at around 70 years. They have been found at incredible depths in the hadal zone starting at 6000 feet deep (19 times the statue of liberty!). More people have been to the moon than the hadal zone. It is a lonely dark place.

Can’t get enough of spooky sea creatures? Discover other fascinating facts by taking a deep-dive into the depths of the sea.


  1. “Japanese spider crab”, National Geographic, www.nationalgeographic.com/animals/invertebrates/facts/japanese-spider-crab
  2. “Anglerfish: 7 Facts About This Scary Sea Creature”, WorldAtlas, www.worldatlas.com/articles/anglerfish-7-facts-about-this-scary-sea-creature.html
  3. “8 Interesting Facts About the Blobfish”, AquaViews, www.leisurepro.com/blog/explore-the-blue/8-interesting-facts-blobfish/
  4. “The Creature Feature: 10 Fun Facts About the Greenland Shark”, Wired, www.wired.com/2014/02/creature-feature-10-fun-facts-greenland-shark/
  5. “Amazing Facts About the Colossal Squid”, OneKindPlanet, onekindplanet.org/animal/squid-colossal/
  6. “12 Incredible Black Swallower Facts”, Animal Stratosphere, animalstratosphere.com/black-swallower-facts/
  7. “Goblin shark facts”, Fact Animal, factanimal.com/goblin-shark/
  8. “Giant Grenadier”, INaturalist, www.inaturalist.org/guide_taxa/969207