The objectively freaky-looking frilled shark doesn't show up that often. It spends its time more than 3,000 feet under the sea, and rare sightings — like the most recent one last November off the coast of Portugal — always make headlines. The frilled shark is called a "living fossil" because so many of its weird characteristics date back to prehistoric times.
"Frilled shark" may sound like an oddly fashionable name for an animal with such little flair, but it's actually named for its frilled gills. Rather than having separate gills like all other sharks, its first pair goes across its throat.
These strange creatures live deep below the ocean's surface and are very rarely seen. But never fear! There are other bizarre, ancient sharks swimming around the ocean to meet, too. Each one has its own strange features, and most are pretty reclusive too, luckily for us.
Another creepy shark with a misleadingly pleasant name, the cookiecutter shark makes circular holes in its prey when it eats lunch. Relative to its size, it also has the largest teeth of any shark. Please stay in the deep ocean, cookiecutters!
The sixgill's characteristic number of gills make it more closely related to fossilized sharks than to the sharks of today, which have five gills. Researchers were surprised this year to discover a new sixgill shark in the Atlantic Ocean. It had been hiding in plain sight by looking exactly like the sharks that hang out in the Pacific and Indian oceans. Sneaky!
3. Ghost Shark
Ghost sharks were caught on film for the first time in 2016. That's when they were introduced to the world as the zombie-looking creatures they are. As a fun bonus, they also have sexual organs on their heads. Maybe evolution made sharks a bit more, uh, practical over the years?
4. Goblin Shark
These freaky creatures have been hanging around the ocean for 125 million years, making them the oldest-known species of shark on the planet. They may look pink, but that's because their skin is translucent — you can see their pink flesh underneath.
Fewer than 50 goblin sharks have been spotted by humans, so we're sorry to say you might not get to see these translucent creeps in person.
While not a living fossil, these sharks make our list because of their impressive lifespans. Greenland sharks are so elusive, it was big news when researchers captured video footage of them in March 2018. We don't know a lot about these strange creatures, but we do know they can live for hundreds of years. One caught in December 2017 was estimated to be 512 years old.