You are in the outback deserts of Australia, 50,000 years ago.

You were inspecting a dry creek bed for core samples when a shadow fell across my notebook—a shadow too large for a kangaroo, too deliberate for a wedge-tailed eagle.

You looked up, expecting a stray cow. Instead, you saw a reptilian king.

It was lying partially submerged in the dust and sparse shade of a bloodwood tree, maybe thirty feet away. Its skin was a mosaic of charcoal grey and mud-brown, armored with small, bony, bead-like osteoderms. It looked less like a modern lizard and more like a fossilized nightmare brought to life.

You froze. Your training said, "don't run," but your instinct was screaming to panic. The creature—Megalania—was enormous, easily twice the length of a 4WD truck.

It didn't notice you at first. It was scenting the air, a massive, forked tongue flicking out, tasting the heat. When it finally turned its head toward you, the sheer size of its skull was breathtaking. Its jaws were slightly parted, revealing serrated, knife-like teeth coated in saliva.