The presence of an aggressive group mind hidden in clumps of coral would have been bad enough. What made the whole thing infinitely worse was that the polyps could also invade and live inside living beings: Humans and Bellidos and Juriani and pretty much everyone else in the galaxy. A polyp hook could move in with just a scratch of the coral and reproduce enough polyps inside their host to create a new Modhri mind segment.

In some ways it was like the terrorist wars of the early century. Only worse, because the newly created walker was completely unaware of the fact that he or she had been co-opted into the Modhri's quiet war of conquest. Most of the time the colony lay quiet, occasionally making subtle mental suggestions that the host would usually obey and afterward find a reason to rationalize away.

But that was under normal circumstances. Under more urgent need, the Modhri mind segment could take complete control of his host, overriding the resident mind and turning the body into a sort of life-sized marionette. The host would have no memory of that period, but would merely end up with a strange blacked-out chunk of his or her day.

Even then, if the Modhri was clever, he could avoid suspicion. A short blackout could be rationalized in any number of ways, especially if the walker was accustomed to drinking intoxicants. Since most of the rich and influential who were the Modhri's targets of choice had learned social drinking at an early age, it was an easy and obvious explanation for the Modhri to push.

If that wasn't bad enough, each walker mind segment could also telepathically link up with the segments of other nearby walkers, or with outposts of the coral itself, creating a larger, smarter, more dangerous mind. A given Modhri mind segment was never static, but continually added pieces and information to itself as new walkers came into telepathic range and losing pieces as old ones moved away off the edge of its consciousness. The result was a fluid, ever-changing opponent that was as hard to pin down as a drop of mercury.