The Enormous Word by William Oberfield - The blue men had ravaged Terra and reduced Winston Eberly to a contemptible insect. Now here he was, complaining of indigestion!

Hurry! Hurry! Run as fast as you can go to the big tree! Crouch beneath its branches and hide, staring up through its open spaces to see if anything is glinting in the clear sky. Anything there? Oh God, yes! No, it's only a bird, a small cloud drifting. Now! Dash madly, crawl on your belly, fight on to the next place of concealment!

Winston Eberly knew he was talking to himself, but he didn't give a damn. He was sweating and sick from exertion, half mad with burning thirst and bleeding from an unknown number of cuts and scratches, but that didn't matter either. The only thing that had any real meaning or value was the stuff in the box in his pocket.

He slapped the pocket with a dirt-encrusted hand. "Good old box! Good old U-235!" he mumbled feverishly. "You'll pull us out of this mess we're in. You'll show the blasted men from space they're not playing with children!"

Pausing in shadows he looked again at the sky. All blue and quiet. Nothing stirring up there, nothing glinting. But they were there all right; they were always there. Maybe they were in the stratosphere, maybe above it, or about to streak low across the sky from horizon to horizon in the twinkling of an eye.

Men from space. Hateful, sadistic, repulsive men from outer space! Oh, how overbearing they were; how greedy and cruel and how sure of themselves! They had reason to be confident, of course. They had simply stood far off in space and shrouded the entire world in a terrible radiation that brought unconsciousness to all and death to many. And something in that radiation had sought out every particle of refined Uranium and Hiroshimaized the world.