You are in the swamplands of North Africa, 95 million years ago.

The air in the Cretaceous African river system was thick, hot, and smelled of rotting fish and wet mud. You stood on the edge of a vast mangrove forest, watching the water. Then, it erupted.

It wasn't a roar that alerted you, but a massive, crocodilian-snouted head breaching the surface, water cascading off its dark, scaly skin. It was a Spinosaurus—a, roughly 50-foot-long, 10-ton behemoth. Its nostrils were positioned high on its snout, allowing it to breathe while almost completely submerged. It was terrifyingly silent, acting more like a gargantuan heron than a land predator.

It moved with a strange, undulating motion, its dense bones giving it a low profile in the water, while its paddle-like tail, reminiscent of a crocodile’s, provided silent thrust. As it moved closer to the bank, the sail—a massive dorsal fin supported by long spines—cut through the surface, a signal of dominance in these rivers.

Just then, it turned its attention toward the bank, noticing your presence. A low, vibrating hiss escaped its throat. It didn't charge on land; it simply stood its ground, staring at you… menacingly…