I eased my head over the top of the hill, and saw them: zompires.
Different people might call them other things, but we called them zompires. Unless they were particularly weak and damaged specimens, in which case we called them Vambies.
If you saw them in the early stages of the infection, half-blind and off-balance and uncoordinated, you wouldn't think they were much of a threat - and you'd be right. But as the parasite spread, killing and replacing human flesh like some fungous cancer, they grew faster and stronger and much more stable.
Fully developed zompires looked like nothing so much as a black-and-white photo of a skinless corpse, the grain of the muscles and the lines of the veins sketched in lighter and darker grays. Here and there they might be missing a limb, where something had rotted off before being completely assimilated, but that was usually just fingers and toes. It wasn't enough to slow them down or throw them off.
Very little threw them off. They didn't have a circulatory system, like we did; no matter where you cut them, they didn't bleed out. Their organs were redundant and distributed; a shot to the heart or head might stun them, but it wouldn't finish them. Even decapitation didn't always do it. You needed something systemic: intense heat, or extreme cold, or truly massive physical damage. They could starve, but not as easily as human beings could; ditto suffocation.
This wasn't a large group; maybe a dozen specimens, but they were all fully developed. That meant that they would react intelligently to whatever we did. It also meant that they had access to their full range of senses, which we didn't completely understand. We knew they could spot us up to about three hundred yards out, but we weren't sure how they did it; and we knew they had some other way of finding people, since they drifted towards us - or anyone else - across much longer distances than that.
Ordinarily, we dealt with zompires from as far away as possible, using rifles. With blood-addicted bandits sniffing our tails, we couldn't afford to make that much noise. And the ground ahead was pretty open; if we tried to circle them, we were pretty much committing ourselves to running. Maybe we'd make it, or maybe we'd end up cornered and overrun; no way to tell in advance.
I eased back down, and went to rejoin the others. "Drive through them," I said. "If we don't find shelter, we're done."