You are in the mangrove swamps of North Africa, 36 million years ago.

The air was thick, humid, and smelled intensely of sulfur and rotting fruit. You stepped cautiously over the buttress roots of a mangrove-like tree, the mud sucking at your boots. The water here was shallow, barely knee-deep, but murky, hiding the massive, submerged root systems of the lush, tropical swamp that once covered northern Africa.

Just then, you spotted a creature in the distance. It was colossal, easily 11 feet long and nearly 6 feet tall at the shoulder. The animal was half-submerged in a deeper pool, its thick, gray, elephant-like skin glistening in the humid haze. But it was the face that struck fear into you. Two massive, conical bone horns, each over a meter long, protruded from its snout, creating a violent, "double-horned" silhouette. Behind them, a second, smaller pair of horns sat over its eyes.

The giant was browsing on tough ferns. It didn't lift its head immediately, which you realized was because its massive horns blocked its forward vision; it had to swing its head to the side to see what was directly in front of it. You froze as it made a low, huffing sound—a sound that echoed from its massive nasal cavity, perhaps amplified by the hollow cores of its huge horns.

Suddenly, the wind shifted, and the beast caught your scent. It turned its head, the twin monstrous horns pivoting toward you. With a surprising, lumbering swiftness, the 2-ton animal charged toward the shore, the water churning around its legs. It was designed to move through thick mud, not run, but in the close quarters of the swamp, it was terrifyingly fast.