You are in the deep oceans of Australia, 113 million years ago.

The sea was deceptively calm, a shimmering sheet of blue under the cold, cloudy sky. You were in a 20-foot outboard motorboat, near the edge of the inland ocean, when the sonar starts to act up.

It wasn't a school of fish; the reading showed something colossal moving fast, hundreds of feet below. Just as you realized, the water erupted.

A massive, black skull—longer than a car, with teeth the size of bananas—broke the surface just ten yards to my right. The water displaced by its four massive flippers created a vortex that threw my boat sideways.

A Kronosaurus, you quickly identified as you stumble.

The creature was easily 35 feet long, its slick, black back cutting through the water. It was an ambush predator, perfectly suited for this, utilizing the speed of the deep to attack from below. And now it is hunting you…