You are in the oceans of South America, 5 million years ago.

The water of the Miocene-era Peru coast was unusually warm, but a sudden silence had fallen over the reef. You hung in the blue, your senses screaming that something was wrong.

Then, you saw it—a shadow larger than a ship, moving not with the slow grace of a filter-feeder, but with the calculated precision of a killer.

A Livyatan, and it was beautiful—and terrifying.

Roughly 50 feet long, it dwarfed your presence, its skin a mottled, dark grey-black. As it passed, you didn't see the tiny jaw of a modern sperm whale; you saw a massive mouth armed with foot-long teeth, interlocking like the teeth of a saw, designed for tearing flesh rather than suctioning squid.

Its eye, surprisingly small against its massive head, rolled in your direction. You felt the pulse of the ocean—a thrumming, powerful wake—as its colossal body surged forward, hunting something far larger than you…