Today's octopuses are intelligent, remarkably flexible animals that lurk in reefs, hide in crevices, or drift through the deep sea. But new research suggests that their earliest relatives may have played a far more predatory role in ocean ecosystems.

Around 100 million years ago, real kraken-like creatures stalked Earth’s prehistoric oceans. According to a study published today in the journal Science, some of the planet’s oldest known octopuses measured nearly 65-feet-long and ruled their underwater domains.

The now-extinct mollusk may have reached up to 60 feet in length, researchers have found

Some octopuses that lived over 72 million years ago were as long as whales. These huge predators may have been the largest invertebrates ever.

According to CNN, Japanese researchers used recently discovered fossils to compare jaw sizes with modern species and found that these ancient cephalopods reached lengths of 23 to 62 feet, with the largest specimens far exceeding any octopus alive today.

Some 80 million years ago, the late Cretaceous oceans were patrolled by 17-meter mosasaurs, long-necked plesiosaurs, and massive, predatory sharks. For decades, the paleontological consensus was that this was the age of vertebrates; anything without a backbone was lunch.

A new study suggests 60-foot-long creatures resembling the mythical “kraken” were top marine predators millions of years ago.