You are in the deep oceans of North America, 75 million years ago.

The sunlight turned the Western Interior Seaway into a blinding sheet of turquoise. You leaned over the side of the survey boat, adjusting my regulator, looking into the warm, late-Cretaceous water. It was surprisingly clear.

Just then, several silver streaks, easily six feet long, darted past the hull. It was a school of Gillicus. Each of these streamlined fish wasn't the hulking, monstrous shape of a Xiphactinus—the dreaded "bulldog fish"—but a sleek, fast, and remarkably, almost gentle-looking predator. It had a kinetic, almost delicate skull, moving with a fluid grace.

You watched as the school of Gillicus fed, not biting, but using a “pipette” mechanism, each of their jaws extending forward to create a suction that instantly hoovered up a cloud of small baitfish. The Gillicus was a perfect, efficient carnivore but surprisingly ordinary-looking creature.