You are in the lowlands of North America, 76 million years ago.

The air in the Late Cretaceous forest of Alberta was thick and humid, smelling of damp ferns and pine. While you were following the edge of a slow-moving river, a low, rasping sound—like coarse sandpaper rubbing against wood—broke the silence.

The ferns parted, revealing not a predator, but a walking fortress. It was a Euoplocephalus, a massive ankylosaur draped in armor that looked more like polished stone than skin. You froze, holding your breath as the morning mist clung to its spiked hide.

It was moving slowly, chewing on low-lying ferns, seemingly oblivious to you. The sheer complexity of its back fascinated you—countless ossicles, plates, and bands of bone shifting as it walked. It was almost twice as long as the skull, you thought, remembering the complex air passages you had studied.

As you take a step back to keep a distance from it, you made a mistake of stepping on a dry branch.

Immediately, the Euoplocephalus ceased eating and senses you. It didn't turn to run. Instead, it went rigid. It lowered its body, grounding itself to the earth, and swung its tail, with the bony club at its end, side to side, creating a perfect defense. The armor along its neck seemed to pull tighter, leaving only its eyes—large and surprisingly dark—visible above the shielding, watching you…