You are in the coastal forests of Eastern North America, 66 million years ago.

The humid air of the New Jersey coast felt heavy, smelling of salt and decay. You were tracking the movement of a herd of Hadrosaurus through the thick fern forest when the world suddenly went silent. The crickets stopped chirping, and the distant calls of younger dinosaurs ceased.

A low, vibrating rumble—felt more in your chest than heard—stopped you in your tracks.

Emerging from the treeline about fifty yards away was a Dryptosaurus. It wasn't the size of a T. rex, but it was horrifyingly efficient. Around twenty-five feet long, its sparse feathered body was a mottled brown and black, but its face was bare, crimson, reptilian skin, showing a snarl of teeth.

It wasn't looking at you, but at the herd ahead. It crouched, its long, powerful hind legs tensed, and it lifted its tail for balance. The "tearing lizard" lived up to its name—when it stepped out, you saw the massive eight-inch claws on its arms dangling, designed to rip into prey.

As it began to surge forward in a rapid, bounding stride, the Dryptosaurus turned its head, its sharp eye locking onto your location for a split second. A cold sweat broke out…