The Scariest Monsters of the Deep

On Halloween we delight in getting a fright from zombies, goblins, and vampires—all the while knowing that they aren’t real. Yet if we were to descend deep beneath ocean’s surface, we’d discover that nature has produced some spook-tacular creatures of her own. Some have numerous jaws, the better to chop up their prey. Others attack their victims with acid. Many have ghoulish sexual appetites.

There are a couple of reasons we don’t need to worry about a run-in with these organisms. For one thing, we’d never survive the frigid waters hundreds to thousands of feet deep that they inhabit. The pressure would kill us, but, “The pressure isn't really a problem for the organisms that live there—they are mostly water and essentially incompressible,” says Will White, a marine biology professor at the University of North Carolina Wilmington. And though an extreme environment, it’s not a variable one. “In contrast to, say, rocky intertidal or coral reef habitats, these are very stable habitats with some of the most consistent conditions—temperature, salinity, oxygen, [lack of] light—of any ocean waters on the planet.”

Another reason not to worry is that, as ferocious as these creatures may appear, most are quite small. “There's not much food down there, and the deep sea is not a very productive habitat,” says White. “So, there is not enough energy to sustain a large-bodied predator.”

Here’s a sampling of the scariest-looking monsters that lurk in the deep.

Zombie Worm: The deep sea is haunted by its own version of a demented dentist—the zombie worm. These three-inch-long creeper-crawlers thrive in the graveyards of the abyssal zone, drilling into the bones of deceased whales. They lack a mouth, stomach, and anus, so how do they eat? They secrete an acid that dissolves the bone, which then releases fat and protein. Symbiotic bacteria living inside the worm digest these molecules. When it comes to reproduction, the creatures practice sexual parasitism. Microscopic males live inside the females’ bodies, sometimes in quantities of a hundred or more.

Deep-sea Blob Sculpin: These sad-looking creatures look more like ghosts than fish, and were recently dubbed the “ugliest animal in the world.” Maybe so, but their looks are the key to their survival. “The gelatinous appearance everyone seems so critical of is a brilliant adaptation allowing this fish to be slightly less dense than water,” says Craig McClain, assistant director of science for the National Evolutionary Synthesis Center, chief editor of Deep Sea News, and a professor at Duke University. “This slight positive buoyancy allows P. marcidus to hover over the seafloor without expending energy, a huge advantage in the food poor deep sea.” They feed on sea pens, mollusks, and crabs that float their way. Found around the Pacific Coast of Japan and California and around the Bearing Sea, and live up to 9,000 feet deep. The ghoulish globs do have some defenses—pointy spines on their gills that they use to ward off predators.

Deep-sea Anglerfish: Despite its mean-looking bite, this fish is small, reaching four inches long. You may remember the deep-sea anglerfish, which lives at depths of 1,000 to 5,700 feet in the Gulf of Mexico, Caribbean Sea, and Atlantic Ocean, from Finding Nemo (it nearly ate Dory and Marlin). Females have a bioluminescent lure at the end of an illicium, or long rod, that they dangle to reel in other fish. When their prey swim toward the glow, the anglerfish chomp at their victim, sometimes consuming fish twice their size. They easily lure in prey by floating around, so they’re light and lack muscle. These fish are a prime example of sexual parasitism. When a free-swimming male latches on to a female, he hold fast with his sharp teeth. He eventually fuses with her, connecting to her circulatory system and becoming entirely dependent upon her for survival. A single female can carry up to eight males.

Vampire Squid: Long thought to be a predator—its scientific name, Vampyroteuthis infernalis, translates as “vampire squid from hell”—this cephalopod hangs out and waits for dinner to come to it. It consumes “an abundance of marine snow raining down, consisting largely of poop, dead bodies and mucus discarded by other ocean life,” the Monterey Bay Aquarium reports. Unlike other squid, vampires use fin propulsion over jet propulsion, lack ink sacs, and don’t change color. When threatened, they flash bright photophores on their arms and twist in circles. And just before their escape into the abyss, they excrete mucus covered with blue bioluminescence, which holds their predator’s attention. Like many deep-sea creatures, females are remarkably larger than males.

Giant Isopod: These bottom dwellers are one of the largest crustaceans, extending to about 13 inches in length. They’re found around the globe at depths of 550 to 7,000 feet. Like the pillbug, they curl their strong, thick skeletons into a ball when threatened. And they’re always on the hunt for a meal. “They’re scavengers and opportunistic predators,” says McClain. “They have amazing fat reserves because they can go quite a long time without feeding,” up to eight weeks in aquarium environments.  The crustaceans are in a constant state of semi-hibernation, but they’re quick to act when a prey passes by: The snap it up with their four jaws.

Goblin Shark: These 12-foot-long bottom dwellers live at depth of 1,000 to 4,300 feet. They have 26 teeth on their top jaw and 24 on the bottom. When prey comes their way, they shoot their jaw forward and snatch it up. The long, flattened snout above their jaw is covered in electroreceptors that they use for hunting. Little is known about this shark species. Only 12 individuals have been caught, all as by-catch from bottom trawls, longlines, and deep-sea gill nets. Like their shark relatives, they’re ancient: Fossils date back more than 100 million years.

Pacific Blackdragon Fish: Slithering through the deep ocean, these sleek, serpent-like fish haunt tropical and temperate waters of the eastern Pacific. This species exhibits one of the most extreme cases of sexual dimorphism: The females grow to 16 inches, while the males only reach two inches. Females possess a lure, much like the anglerfish, and have barbells on their bottom jaw that sense prey. Some of their prey is bioluminescent, but they’re unlikely to catch a glimpse of these fish—their black stomachs act as camouflage.