It moved easily beneath his hand. He was tense now, watching the great expanse of floor a hundred feet below. His surmise was correct. A tiny crack appeared there, extending the length of the floor. And upward from it came light--greenish, terrible light which he'd felt before, which he knew was the Entity itself, eager to lash outward! Almost, Ketrik hesitated. But he forced his hand to move the wheel. The crack widened as the floor moved away on either side. Gradually he could see the Entity, the very bulk of it--maddening, impossible--but there it was! Fully a hundred feet across, greenish and blinding! It was roughly globular, seemed to be a giant brain slowly pulsing and evilly alive, yet somehow it was more than that. It was quasi-amorphous, writhing and changing shape and trying to heave itself upward! Tentacles lashed out--tentacles that seemed to be solidified light, seeking ... seeking for sustenance! It began to move upward. Up between the walls on a sliding platform, to a point just above the floor, where it stopped. Some of its light touched Ketrik, beat against his helmet and surged about him, tearing with cold fingers at his beryllium suit. In his absorbing interest he had almost forgotten the controlling rays! He hurled himself at the panel. With reckless sweeps of his hands he flicked on the studs. [Illustration: _It began to move upward ... to beat against Ketrik, surging ... tearing._...] He had been just in time. The white rays, lancing out from the walls, now formed a gorgeous criss-crossing pattern that held the Entity in leash. It writhed and cowered. Slowly its own tentacles of light drew back. It lay in seeming quiescence. But even then Ketrik received its thought-emanations, as they crashed with frightening impact upon his brain. Yes, the thing was alive and evil. Too long had Dar Vaajo held it in subservience. It wished to escape these barriers, launch out for itself. There was sustenance aplenty on Mars, and it would grow titanically. Then would come Earth--and there were many other planets. Perhaps the Entity sensed Ketrik's rising horror. Perhaps it guessed what he meant to do! For now, despite the concentration of rays, it tried to lash out in new fury. Ketrik laughed then, a bit wildly; laughed in mockery and joy, seeing the thing in thrall, watching its futile efforts against the barriers.... Then the laughter died in his throat. Something was happening. The rays, the controlling rays across the walls--one by one they were blanking out! One by one, then suddenly whole rows at a time! * * * * * Ketrik whirled to the control-panel. Another figure was there--Dar Vaajo! Somewhere he had obtained another protective suit, had entered silently. Now he was blanking out the control-rays, enough of them to allow the power of the Entity through!