Earth used to be home to some creatures that look like they were designed in a lab gone wrong. From oversized predators to bizarre, hard-to-imagine species, the fossil record is full of animals that feel almost unreal today. Here are 30 weirdest animals that no longer exist.
Hallucigenia
Hallucigenia looked like it was built upside down on purpose, with spikes on its back and tentacles on its head that scientists originally couldn’t even figure out the correct orientation of.
Opabinia
Opabinia had five eyes and a single claw-like trunk, making it look like a creature designed without a blueprint.
Anomalocaris
Anomalocaris was once considered three separate animals before scientists realized it was one massive ocean predator with a circular jaw.
Dunkleosteus
Dunkleosteus had bone armor instead of teeth and could bite with one of the strongest forces of any fish ever.
Helicoprion
Helicoprion had a terrifying spiral of teeth in its jaw that looked more like a circular saw than a mouth.
Tully Monster
Tullimonstrum gregarium is so strange that scientists still debate what it actually was, with a body like a worm and eyes on a stalk.
Thylacine
Thylacine looked like a dog but was actually a marsupial with stripes and a stiff kangaroo-like tail.
Doedicurus
Doedicurus carried a massive spiked tail club that could crush predators like a living wrecking ball.
Glyptodon
Glyptodon looked like a Volkswagen Beetle with legs and could fully hide inside its armored shell.
Paraceratherium
Paraceratherium is one of the largest land mammals ever, standing tall enough to eat leaves from treetops like a giraffe.
Megalania
Megalania was basically a Komodo dragon scaled up to terrifying proportions, possibly reaching 5–7 meters long.
Deinosuchus
Deinosuchus could grow over 10 meters long and likely hunted dinosaurs that came too close to the water.
Titanoboa
Titanoboa reached lengths over 12 meters and could weigh more than a small car.
Andrewsarchus
Andrewsarchus is known mainly from a giant skull, and it may have been one of the largest land predators of its time.
Moropus
Moropus looked like a horse but had huge claws instead of hooves.
Chalicotherium
Chalicotherium likely walked on its knuckles like a gorilla while using claws to pull down branches.
Platybelodon
Platybelodon had flattened tusks that may have worked like a shovel for stripping vegetation.
Deinotherium
Deinotherium had tusks that curved downward from its lower jaw, unlike any modern elephant.
Sivatherium
Sivatherium looked like a mix between a giraffe and an elk, with massive branching antlers.
Ambulocetus
Ambulocetus could walk on land and swim in water, basically a “walking whale” stage of evolution.
Basilosaurus
Basilosaurus looked like a giant sea serpent and even had tiny hind legs.
Josephoartigasia
Josephoartigasia was a rodent the size of a rhinoceros with teeth strong enough to crush tough vegetation.
Megatherium
Megatherium could stand on its hind legs and was as tall as an elephant when fully upright.
Diprotodon
Diprotodon was the largest marsupial ever, weighing over two tons.
Quetzalcoatlus
Quetzalcoatlus had a wingspan up to 10–11 meters, making it one of the largest flying animals ever.
Therizinosaurus
Therizinosaurus had claws over 70 cm long that looked like scythes on its hands.
Opisthocoelicaudia
Opisthocoelicaudia is unusual because it’s one of the few giant dinosaurs discovered without a known head.
Daeodon
Daeodon is often called the “pig of doom” due to its massive skull and bone-crushing jaws.
Pikaia
Pikaia is one of the earliest known relatives of all vertebrates, including humans.
Gigantopithecus
Gigantopithecus may have stood up to 3 meters tall and lived in Asia, making it the largest ape ever known.
