Pod People!

In 1950 they listened to Harry Fleischer and a small midwestern town was wiped off the map.
Men, women, children, dogs and cats, all gone, poof!
Quarantined and cauterized, white nuclear surgery.

In 1973 they ignored Donald Kent and the pods spread out of New England and into the rest of the country.
By 1980 they had taken all of Canada and everything north of the Mason-Dixon line.
Things, as always, were different in the South.
They bombed — conventionally — every major city, every large town, safe from the deadly heat in air conditioned bombers, safe in the high atmosphere, far from the fires that bloomed as in Dresden, in Atlanta, in Birmingham, in Brownville, in Mexico City, in Buenos Aires.

What was left of humanity took to the hills, hid in the jungles and the dogwoods, Andes, Ozarks, Sierra Nevada.
And married, and sweltered, and interbred, and mutated.
The stock was so small, the culture so cramped.

In 1996 they died, sterile, and the pods lifted from the fields.
Humanity came down from the hills.
The open air terrified them, the bright light hurt their eyes.