question:  How did Ned become a mummy?
context: A scream of brakes, the splash into icy waters, a long descent into alkaline depths ... His car hit the white-painted wooden rail sideways, crashed through, tumbled down a steep slope, struck a huge boulder, bounced up a little, and arced outward, falling as gracefully as a swan-diver toward the inky waters of the Pit, fifty feet beneath.... Ned Vince was still dimly conscious when that black, quiet pool geysered around him in a mighty splash. Movement was slower now, as he began to sink, trapped inside his wrecked car. Time, the Brother of Death, and the Father of Change, seemed to wait.... A launching catapult for the last space ships built by the gods in exodus, perhaps it was—half a million years ago. Loy Chuk had flown his geological expedition out from the far lowlands to the east, out from the city of Kar-Rah. He could think and dream and invent, and the civilization of his kind was already far beyond that of the ancient Twentieth Century. The dry mud that had encased it like an airtight coffin, had by now been chipped away by the tiny investigators; but soiled clothing still clung to it, after perhaps a million years. A mineral saturation that had held time and change in stasis. Not the star-conquering demi-gods, but the ancestral stock that had built the first machines on Earth, and in the early Twenty-first Century, the first interplanetary rockets. A strange accident, happening in a legendary antiquity, had aided them in their quest for knowledge. The final instrument he used to test the mummy, looked like a miniature stereoscope, with complicated details. Though devoid of moisture, the mummy was perfectly preserved, even to its brain cells! Medical and biological sciences were far advanced among Loy Chuk's kind. It might move, speak, remember its past! With infinite care it was crated in a metal case, and hauled into the flying machine. Flashing flame, the latter arose, bearing the entire hundred members of the expedition.
output:  A combination of the alkali and mud his body had been soaked in. Also, the years of dryness after the world became a desert.
options:  Loy Chuk's workers wrapped Ned's body in strips of cloth to preserve it in transport.  The earth became a desert wasteland. All the moisture was leached from the corpse.  A combination of the alkali and mud his body had been soaked in. Also, the years of dryness after the world became a desert.  The body had been devoid of moisture for a million years.