You are in the shallow seas of Germany, 150 million years ago.

The sun was blinding, reflecting off the warm, shallow waters of the Solnhofen Sea, a turquoise lagoon dotted with islands that would make up modern-day Germany. You were by the edge of a muddy islet, watching the marine ecosystem in the lagoon, when the water suddenly turned murky nearby.

A large, molten brown-greenish shape broke the surface, but it wasn't a shark.

It was roughly ten feet long, slender, and incredibly streamlined—a Geosaurus. Unlike modern crocodiles, this creature had no visible bony armor (osteoderms); its skin was sleek and smooth, tailored for speed. Instead of clumsy limbs, it paddled with modified flippers, and its tail ended in a vertical, crescent-shaped fin, almost like that of a modern mako shark. As it briefly submerges in the surface, leaving a smooth wake, its jaws opened wide, revealing a sharp-toothed maw designed for slicing quickly rather than crushing.

The Geosaurus didn't attack immediately. It swam in a slow, calculated circle, with intense curiosity, assessing if you are food or a threat…