The Machine rolled over the dusty plains, as tall as a hundred men. Those huddled in the caves recognised its shape from the stories, but it was bigger this time. Whoever kept sending them was determined. Relentless.
Sheriff Deerborne tried to keep the people calm as they shivered in the dark. He always projected an impression of patient competence, in charge of every situation. But the entire town had been hiding for nine days now, and his resolve was getting close to cracking point.
"Sheriff, when is it going to stop? When can we go home and live our lives in peace?"
"Miss Dorothy, I'll tell you again, this Machine will die, just like the others. I don't know when, but as soon as it does, you and your children can go home."
"It's just not good enough, Sheriff!" said Miss Dorothy, re-settling her youngest boy up on her hip. "We have to find out what it wants and stop it!"
The Sheriff raised his voice and hitched up his gun belt the way he did when he meant business. Everyone in the cave could hear him easily. "We will all go home once the Machine has run its course. Not before. It's not safe. And we can't know what it wants if it won't communicate."
"So go out there and try, why don't you?" asked one of the young men.
Deerborne couldn't see which, but he glared in that general direction.
"Alright. I'm going outside."
The people looked somewhat mollified by this, but they were clearly uneasy. He picked up his rifle and crept out of the cave, telling everyone to stay down, keep quiet. He crept over a ridge to get a good look at the multi-wheeled monstrosity. They were right. It looked like the stories said. He took a closer look through the scope of his rifle, just in time to see the head of the Machine turn, ponderous and slow, and spit a ferocious ray of fire. It burned through rocks like they were nothing, and they wafted away in the thin breeze, utterly destroyed. The machine turned and rumbled over in that direction to investigate its handiwork.
When his blood stopped running cold and his legs would support his weight again, Deerborne shuffled quietly and carefully back to the cave. Immediately he was mobbed.
"What did you see, Sheriff?"
"What does it want?"
"When can we go home? I want to go home!"
All Deerborne could do was shake his head. The monstrous Machine outside was here to find them and destroy them. No question about it. It would be a long time before the Martians could go back out of their tiny caves again.
Outside, the Machine rolled on, oblivious, inexorable, and emotionless except, of course, for its Curiosity.
The main criticism I gathered from the voting comments was that the science wasn't quite right. I try not to let science get in the way of a good story, but there are plenty of sci-fi fans who need to have both. I get that. When someone gets computers wrong on TV or film, it's pretty jarring to me, and for a while that's all I can see. Hardness in sci-fi is a good thing, and I could have made this one more accurate with a little research.
Mokalus of Borg
PS - I don't think I could have made it good enough to win in the short contest time.
PPS - I do still have one horse in the race, though.