The trip back was a wild one. Burt tucked his son under one arm and leaped. He kept low to the ground this time, skimming its surface, sometimes leaping as much as seventy feet with one bounding stride. With each stride, the ground became more spongy, and Burt realized with a sinking heart that the surface could never hold the spaceship up. It would be the same as if it had plunged through the gaping maw in the hard rock with the Havelock--either way it would be gone. Johnny liked the ride. Every time they landed, he would say, "Again, pop. Again!" And wordless, Burt would leap once more. Once he jumped high and he thought he saw the spaceship gleaming in the rays of the sun. But that was impossible. It would surely sink. And then he came down and he did see it. It was there, on a hard expanse of flat rock, where he had left it. Here the ground seemed normal-- He heard Marcia's scream before he saw her. Then she came around the hull of the spaceship, dragging Joan. Screaming again, she fell flat. * * * * * Something whizzed by her head, and even from this distance Burt could see that it was a rock the size of a watermelon. She got up again, and she ran forward, but then a whole shower of rocks came after her, smaller this time, two handfuls of egg-sized rocks, thrown by an invisible giant. He had to be invisible--Burt could see no one. Yet the rocks were being thrown, somehow. Or--the thought suddenly occurred to Burt--they were throwing themselves. The rocks moved under their own power. It was a wild thought and a crazy one, but it made sense. Every other part of the planetoid was soft and spongy. But here--near the ship--the surface was still hard. And rocks were being thrown. Burt could tell this had been happening for a long time, because the hull of the ship was scarred from the fusilade. It was unreasonable to suppose that this tiny area, alone of the entire sphere, could not become spongy. Then there was a reason why it remained hard--and where there was reason there was sentience. And further, why hadn't a big stone been thrown, one large enough to crush their Pacemaker as the Havelock had been crushed? There certainly were enough stones around-- Everything indicated a _game_. Something was playing with them. They were easy prey, they were dead ducks--but something was having fun with them first. They were goners, they didn't have a chance, and that something needed the activity and the recreation. It was a sadistic game. Back on earth, some of the kids had stripped the wings off flies, made them hop about dizzily, helplessly, until they tired of the sport. And then they had crushed them.... The planetoid was playing with them! Burt called: "Get inside the ship, Marcia! Inside!" "I can't. If I stand still long enough to manipulate the lock, these stones will get me. Burt--" "I'm coming!"