You are in the swamplands of North America, 280 million years ago.

The morning mist was thick over the muddy banks of the Early Permian river, hanging low over the giant horsetails and calamites. Your breathing was ragged, still recovering from navigating the dense, humid undergrowth.

A soft slurp sound broke the silence. You instantly take cover, crouching behind a moss-covered log, before peering over.

Slowly, from the narrow channel between two thick, muddy banks, a snout emerged. It was nothing like the deep, heavy skull of a Dimetrodon you had seen earlier in the season. This was long—incredibly long—and slender, resembling a monstrous, prehistoric crocodile, but holding the same spined sail, but shorter, that characterized the apex predator of this era.

Secodontosaurus, perhaps? You thought.

The creature pulled its 9-foot body from the water, its belly scales scraping against the mud. It was a terrifyingly sleek killing machine, yet strangely graceful.

Crawling to the log that you were hiding behind, it proceeds to use its long, narrow snout to poke delicately into a crevice under the bark, seeking out small burrowing amphibians that had sought refuge there. You could see the teeth as it opened its maw, slender and perfectly adapted for grabbing slippery prey rather than tearing thick flesh.

Then, the creature stopped and flinched. The sail pivoted as the creature turned its head. Those cold, yellow eyes locked onto your position…