The Triomed advanced stealthily across the floor of the dark cell toward the sleeping figure huddled in the corner. After the long, lonely voyage, the nearness to a host filled the Triomed with eager anticipation.

The tiny spaceship that had carried him into this lush planetary system far from the galaxy’s heart lay well hidden behind him. So far as he could tell, his descent had not been detected, and that was as it should be--for he was a Triomed and a scientist. One of the finest in the service of his dying race. Dying that is, until now, he thought. No longer would the race of Triomeds weaken and die for lack of suitable hosts. This third planet of the yellow sun was a paradise thick with warm-blooded biped mammals...

The sleeping creature stirred uneasily, as though sensing the approach of danger. The Triomed froze into immobility. It was unlikely that he could be seen, he knew, though the sense of sight was only a synthesized abstraction to him. It was not one of his own proper senses, but he had been able to detect at long distance that almost every living creature on this planet received impressions through certain specialized organs mounted on and within their structure. There were plants, of course, as there were on Triom, but they were unimportant.

There were viruses, too, and he had been afraid when he had discovered this fact that he had arrived too late. But the first attempts at establishing communication had relieved the Triomed of his fears. The indigenous viruses were primitive; not at all like his own illustrious ancestors of ancient Triom.

The sleeping biped relaxed and the Triomed inched forward again, a flat, almost two dimensional smear of glistening matter on the floor in front of the biped.

From high above the planet’s night side, the Triomed had sensed the city. He had absorbed its shape and size and meaning while his craft settled through the heavy, oxygen-rich air. It was not enough that his instruments told of suitable hosts. He was a scientist and believed in absolute proof. Also, he had been in space long--without the satisfaction of a host--and he yearned for the rapport, the domination of a warm-blooded creature.

There had been a dark segment in the brilliant pattern of the city. An island of solitude amid the myriad confluences. It was there that he had landed his tiny probe ship and hidden it among the thickly wooded glades. Almost immediately he had sensed the nearness of many creatures. Insects, plants, warm-blooded quadrupeds and bipeds. There had been machines and buildings and winding roadways among the trees. Darkness had covered his progress until at last he found himself near the sleeping creature, ready to infiltrate and take command.

The glistening shape elongated, became a thread-like tendril of almost gossamer thickness. It touched the flesh of the sleeper and thrilled with pleasure. Cautiously, the Triomed moved up the hairy leg, an invisible strand of alien life close to the warm skin. Presently, the strand found the opening it sought. It slithered imperceptibly into the moist warmth of the sleeper’s nostril, moved through the tear-duct into the space behind the eyeball. Here it probed through muscle and membrane along the base of the brain, seeking the pineal gland.

And found it, penetrated it, coiling like a microscopic serpent within the gland. A surge of pleasure went through the Triomed. Here was safety. The host was large, powerful and vibrant with life. Quickly, the Triomed established dominance. It was shockingly easy. The creature’s mind was immature, primitive. Briefly it struggled and then died as the alien poisoned the identity centers of the brain.

New sensations poured in through unfamiliar sense organs. Sounds of the faraway city, small sounds from the many living creatures in the darkness. Smells and sights and pressures from all about him presented themselves--were evaluated and recorded in the atomic structure of the Triomed.

He was now equipped, he reflected with satisfaction, to carry out further exploration. In the guise of the indigenous biped he could roam among the natives at will. He remained in a sitting position, however, while he familiarized himself with his host.

He had two articulated appendages fixed to the trunk at a point near and below the skull-case. These ended in complex extremities consisting of five jointed fingers. The same pattern was repeated at the lower end of the trunk, but the extremities were suited there for the carrying of the creature’s considerable weight. Within the trunk were the customary viscera generally associated with warm-blooded beings: lungs, intestines, stomach, liver, bladder, reproductive organs and assorted ducted and ductless glands. It was apparent to the Triomed that his present body was in excellent health. He was greatly pleased.

After some careful experiments, the Triomed rose. If there was a proper method of egress from the cubicle in which he found himself, it was not imprinted on the biped’s brain. For a moment this gave the alien pause. He could, of course, determine the proper method by a tedious process of trial and error, but that would take time and he had no desire to waste the hours of darkness. One wall, he noted, consisted of vertical risers fixed in the substance of the floor and ceiling. Beyond, he could see the darkling woods and the sky-glow of the city. The answer, then, was simple force. He did not doubt there was strength enough in the host’s musculature to distort the risers.

His assumption was quite correct.

Stepping through the bent risers, he picked his way along a narrow walkway lined with cubicles similar to the one he had left. Within them, dark shapes moved or lay sleeping. Some were alert, others were not. But none gave an alarm. The Triomed reached the end of the walk, scaled a fence easily and stood on a surface of wet grass that sloped away from the low dark building toward the woods.

Behind him he heard a shout. A narrow beam of light pierced the night, swinging to and fro with a searching motion. He had a fleeting glimpse of a small biped running down the walk toward the cubicle he had deserted.

The Triomed broke toward the wood with a long loping pace that covered the ground with unbelievable swiftness. The probing light did not find him. Once among the trees he paused and took his bearings. The woods were not thick. He could see the lights of the city through the foliage. They began at the very edge of the trees, where a wide open area could be discerned. Wheeled vehicles moved past with breathtaking speed.

If there was pursuit, it was inefficient, for the Triomed moved through the woods undisturbed until he stood at the edge of the avenue, sheltered by the shadow of a large tree. Most of the traffic was vehicular, he noted. There were few pedestrians. From the noise and odor he classified the vehicles as being powered by internal combustion engines burning hydro-carbons. Primitive. That was good, he reflected. When the fleets of Triom descended on this planet, there would be no science worthy of the name to oppose them.

He waited until there was an interval in the traffic, and then stepped out confidently, crossing the avenue. As he reached the opposite side he heard a screech of brakes and a garbled, choking sound. He did not turn to discover the source of the disturbance until he had reached the shelter of a building on the far side of the walk bordering the street.

A vehicle had stopped at an oblique angle to the lane in which it was travelling, and its single occupant, a very pale-faced biped was goggling stupidly in the direction of the hidden Triomed.