15 Horrifying Creatures You’ll Be Glad Are Extinct


Throughout Earth’s long and tumultuous history, the process of evolution has sculpted an incredible diversity of lifeforms, each adapted to the unique challenges of its time and environment. However, some prehistoric creatures, when brought to light by paleontological discoveries, inspire not awe but a profound sense of relief at their absence from the modern world. Here are 15 extinct creatures you should be glad no longer exist.



Do you fear snakes? Imagine a giant snake capable of crushing cars. Titanoboa lived during the Paleocene Epoch in South America, growing up to 40 feet and weighing between 1,610 and 2,500 pounds. It hunted large prey by constriction, dominating as the largest land predator after the dinosaurs. This creature was a gigantic apex predator and thrived in tropical swampy environments.

Pentecopterus Decorahensis

Patrick Lynch/Wikipedia 

The ocean has always inhabited strange creatures, but during prehistoric times, there were giant monsters like the Pentecopterus Decorahensis. This creature was the oldest known eurypterid, resembling an ancient Greek warship (‘penteconter’) in shape. It measured over 6 feet and had a long head shield, narrow body, and large grasping limbs for hunting prey, which made it a significant predator in early Paleozoic ecosystems.

Hallucigenia Fortis


Another unusual ancient sea creature that had discoverers perplexed is the Hallucigenia Fortis. It was discovered in the Burgess Shale and lived around 500 million years ago in the Cambrian era. The aquatic animal was initially misidentified as Canadia by Charles Doolittle Walcott. Simon Conway-Morris reclassified it in 1977, noting its bizarre appearance with pointy legs and tentacle-like appendages used for scavenging.

Arcdotus Simus 


Even in ancient prehistoric times, some species of bear roamed the lands. Arctodus Simus was the fastest-running bear known, standing up to 12 feet tall on hind legs and capable of speeds over 40 miles per hour. Its carnivorous diet, adapted skull with forward-facing eyes and a keen sense of smell, and powerful jaws equipped for bone-crushing indicate it hunted large herbivores like bison and muskoxen during the Ice Age.



Did you know that a school of piranhas can devour an entire cow in 2 minutes? Now imagine what a giant piranha would be capable of. During the Late Miocene era lived the Megapiranha, weighing about 20 to 25 pounds. It had a biting force of up to 1,000 pounds per square inch, so it could prey on fish, mammals, reptiles, and large-shelled creatures in its river habitat.



Some people fear the ocean because of carnivorous aquatic animals. In ancient times, the Megalodon, a shark, was the largest marine predator ever to roam the sea. It could reach lengths of up to 82 feet and weighed over 143,000 pounds. Sperm whales and killer whales were this shark’s primary choice for food, which shows the sheer magnitude of its size and strength. 



While birds are often seen as beautiful innocent creatures, some of them were once quite terrifying. Take the Phorusrhacidae, for example—it’s known as the terror bird because of its massive head, strong hooked bills, and powerful legs ending in clawed toes. Standing 3-9 feet tall and weighing up to one ton, they were carnivorous predators that used their powerful bills to strike and kill prey.


Wikipedia commons

In ancient times, there were also animals that looked fluffy and cute but were ruthless hunters. The Simocyon resembled a red panda but was the size of a mountain lion, weighing up to 120 pounds. It had carnivorous or omnivorous teeth capable of bone-crushing, and like the red panda, it possessed a radial sesamoid for climbing trees.



The first fossil of the Spinosaurus was found in 1912. Over the years, scientists have put bones together to give us an example of what these creatures looked like when they were alive. This dinosaur had a distinctive sail-like structure on its back, likely used for display or thermoregulation. Contrary to earlier beliefs, it had short legs, suggesting it spent significant time in aquatic environments, possibly swimming or inhabiting shorelines.


 Werner Kraus/Wikipedia

This millipede, 2.6 meters long, was the largest anthropoid in the world. It lived over 290 million years ago. Many fossilized footprints of the Arthropleura can be found on the coast of Scotland. These giant millipedes ate dead plants, nuts, and seeds that scattered the ground. They may not have been apex predators, but their sheer size would have been terrifying to see today. 



Dragonflies are excellent hunters, and they glide with ease when catching their prey. The Meganeura was no different. Resembling modern dragonflies, they were predatory, feeding on other insects. With wingspans up to 27 inches, Meganeura is one of the largest flying insects known. It adapted to open habitats and had spiny legs for catching prey.



Smilodon, commonly known as the saber-toothed tiger, is a well-known carnivore from the Late Pleistocene. Despite its name, it was not closely related to modern tigers. Its massive, deadly sharp canines are adapted for delivering fatal wounds to prey, likely targeting the throat or belly. Unlike modern cats, it had a robust build with a bobtail, suggesting it ambushed rather than chased prey, possibly hunting in packs similar to modern lions.



Some animals can be scary because of their features. In ancient times, most animals had unusual appearances, like the Endoceras. The squid-like animal could reach 10 feet in length and likely had 10 arms lacking suckers, ideal for navigating the muddy seafloor of warm, shallow seas. One notable fossil is displayed at the Science Museum of Minnesota, discovered by a local collector.

Megalania Prisca 

 Arthur Weasley/Wikipedia

Megalania prisca, discovered by Sir Richard Owen in 1859, was the largest known terrestrial lizard, reaching up to 5 meters long. It inhabited various Pleistocene habitats in eastern Australia, such as forests and grasslands. Similar to the Komodo dragon, Megalania was a formidable predator, feeding on large mammals, snakes, reptiles, and birds. 

Tyrannosaurus Rex


This 40-foot-long predator once roamed the forested valleys of what is now western North America. It had an extraordinary sense of smell, which it used to track down prey such as the Triceratops. To add to its features, it was capable of speeds of up to 12 miles per hour for easy prey hunting.


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