You are in the forests of Europe, 166 million years ago.

The air in the Jurassic jungle was thick, hot, and smelled of rotting ferns. You were trekking near a limestone outcrop, when the sunlight suddenly vanished.

It wasn't a cloud.

A massive, jagged shadow—an impossible distortion of sharp teeth, a long, slender snout, and a distinctive nasal crest—stretched over your hands, instantly blacking out the sunlit patch of jungle floor. Thinking that a large carnivorous dinosaur was nearby, you bolted behind a rock for cover. The silence was absolute. The only sound was the abrupt stop of your own breathing.

Slowly, you peer from your hiding spot. But what finally came into your view was unexpected. It wasn’t a big predatory dinosaur.

Emerging from behind the dense cycads was a Proceratosaurus. While only about 10 feet long, the early tyrannosaur seemed monstrous in the dim, sun-dappled foliage. Its dark-feathered, agile body was hunched low, stalking something just beyond you. It reared up to its full height, perhaps five feet at the hip, and letting out a low, vibrating growl that shook your ribs, it snapped its sharp, serrated jaws in the air.