THE leech was waiting for food. For millennia it had been drifting across the vast emptiness of space. Without consciousness, it had spent the countless centuries in the void between the stars. It was unaware when it finally reached a sun. Life-giving radiation flared around the hard, dry spore. Gravitation tugged at it. A planet claimed it, with other stellar debris, and the leech fell, still dead-seeming within its tough spore case. One speck of dust among many, the winds blew it around the Earth, played with it, and let it fall. On the ground, it began to stir. Nourishment.