Schild’s Ladder

Mariama suggested that they try to follow the path of the migration back to its source. "That could lead nowhere, but it’s the only clue we’ve got as to where other life might be concentrated."

This made sense to Tchicaya. They moved the ship closer to the airflowers, and descended along the sparse trail.

Within an hour, the creatures were crowded around the Sarumpaet like coral spawn. When the toolkit probed the Bright itself, it appeared that the airflowers had latched on to a particularly stable current of vendeks; if this broke apart higher up, the specimens they’d encountered earlier might have pursued it as far as it went, and then scattered. The current was useless for transportation — you couldn’t ride it like a thermal updraft, in a world without conservation of momentum — but whether the airflowers were using it as a navigation aid, as a feature to congregate around for breeding purposes, or merely as something to graze upon was impossible to say. The vendeks certainly diffused into the airflowers' bodies, but they still might have been anything from valuable symbionts, sought out by their hosts, to burdensome parasites that came with the territory.

"Can vendeks ever really be prey?" Tchicaya wondered. "They’re the smallest stable objects, so there’s no point seeking them out just to break them down into their constituent parts."

Mariama said, "There are no subunits that you can extract from them and treat as nutrients — nothing analogous to vitamins or amino acids — so when you eat for the sake of eating, you’re infecting yourself. All food works like yogurt. But that doesn’t mean that the only reason to seek out a particular kind of vendek would be to give it a new home. Nothing that crosses your path is going to move aside for you automatically here, so you have no choice but to convert whatever you encounter into a part of yourself. Sometimes the vendeks around you can be incorporated unchanged, but other times you need to have your own tame vendeks invade the graph ahead of you, chewing up whatever’s there as they propagate through — in which case, you want them to be taking on adversaries that they can conquer easily, even if you’re not planning to pillage the corpses for specific spare parts. Whether you call that predation or not is a moot point." She smiled. "Assuming that all this talk about larger organisms makes sense at all, and we’re not just watching a few vendeks traveling in packs, lording it over the rest."

"I wish you hadn’t said that." Tchicaya already found it eerie enough contemplating the identity of these xennobes. Humans had been nothing but a colony of specialized cells, but at least those cells had all been related to each other, and subdued to the point where they could pursue a common genetic goal. In the airflowers, there seemed to be as many vendeks plucked into service from the surroundings as there were specialized ones that appeared only in the creatures' tissues.

"What’s that?" Mariama had spotted something through the floor. She gestured impatiently to the scape, transforming the checkerboard beneath their feet into a completely transparent surface.

A dark shape was spiraling up around the column of airflowers, a sprite-shadow that the probes were yet to fill in. Seconds later, it began to take on details, the colors shifting wildly as the scape improvised palettes to encode the information, then judged them inadequate and started again from scratch.

The probe image showed a dense, branched network of tubes filled with specialized vendeks, cloaked in a more complex version of the eddies that wrapped the airflowers. The tube walls were layer populations, but they extended fine tendrils out into the trapped currents of the Bright. Controlling them? Feeding off them? The scape was unable to track all the dynamics; too much was happening for the probes to capture it all, and many of them were being captured themselves, lost among the vendeks they’d been sent to map.

The new xennobe was ten or twelve times larger than a typical airflower. As it soared past the Sarumpaet, Tchicaya instructed the ship to follow it. Going into reverse was disturbingly easy; the only thing resembling inertia that the ship possessed was the precise distribution of the hull vendeks that chewed their way through the Bright.

When they caught up with the xennobe, it was circling the airflowers closely, moving in on one target. As it struck, the probes showed the two cloaks of entrained Bright vendeks merging; it was impossible to tell if the airflower’s covering had been stripped away or whether the creature pursuing it had deliberately exposed its own inner organs. As the process continued, though, neither party remained shielded from the other. Veins became entangled, endogenous vendeks flowed between the two. The airflower had made no attempt to flee, so it was either insensate, too slow, or a willing participant in the exchange.