You are in the forested plains of Mongolia, Asia, 70 million years ago.

The sun was low over the red sandstone of the Nemegt Formation, casting long, dramatic shadows across the dune-sea. You have been documenting small theropod tracks all morning, but now, a strange, rhythmic rustling caught your attention from a thicket of arid shrubs.

You crouched behind a boulder, pulling your sketchbook closer. Emerging from the brush was not a lone predator, but a flock of bird-like creatures covered with bright, yellow feathers. There were at least six of them.

These must be Avimimus, you thought as you inspect them closely from your spot.

They were spectacular—roughly three feet tall, slender-bodied, and covered in a coat of simple, yellow feathers that shimmered with hints of blue in the fading light. They looked like ostriches designed by a chaotic engineer, with long, delicate legs and short, stubby arms held tight to their sides.

They were moving fast, a coordinated group foraging with a terrifying, efficient rhythm, their movements quick, intelligent, and birdlike.