Rusty, succumbing to his innate get-the-facts complex, asked if the seas contained life, was answered in the negative. But he questioned the statement when they passed a half-submerged creature that weighed well over five tons, heavy clawed limbs rearing stiffly. The air about it was a nausea.

"Mud animal," explained Spike. "Life here came from the mire instead of the sea. With the exception of the Plain, the whole planet is covered with soft mud, thousands of miles deep. It is there that most of the life exists. This one probably got wounded, came blindly up and died."

As the Earthian spoke, he halted, his face suddenly darkened.

Rusty, advancing to him, felt a strong suction beneath his feet. Go back! But he could not turn back, nor go forward.

"Lothar!" yelled Spike, but the mighty Vulcanian was also caught fast in the grim pull.

The mire under the water had softened, like quicksand. It tugged at his feet and legs, pulling him slowly down into the green ooze. He splashed with powerful strokes. He sank deeper.

"Fish!" cried Spike. The lithe Venusian idly tread water beside them, showed little interest. "Get us out of here!"

The water slowly climbed up Rusty's fear-tingling body. He could feel the liquid creeping up, as he was pulled down, into the slime. He strained with all the power of his legs. Seized them with his hands and pulled. He sank deeper, slowly. He could feel the bottomless suction. Like a nightmare in which one falls slowly. It was no nightmare. It was stark reality. Thick water, green ooze. He splashed wildly.

Fish stared from one to the other, curiously.

"Get you out?" he asked.