He had tried to shoot it--he really had. The Federation sent all exploratory teams with weapons as well as food, medical supplies, and tools, and saw to it that even the least athletic of their scientists could fire and maintain a phaser and a plasma rifle. Archaeologists are of necessity hardy individuals, and even at a distance of 50 yards, Crater was more than capable of hitting the creature that stooped over his wife.
The thing saw him before he could raise the rifle; he supposed his hurry to find Nancy, whom he imagined to be lost in the ruins and succumbing to heatstroke or worse, had made his approach noisy. The face that turned to his--it was just barely recognizable as a face--was framed in lank hair, the suckerlike mouth filled with needle teeth. In later days he would reflect that he had been hasty, that for all he knew the creature could have been coming to Nancy's aid, could even have been the key to understanding the artifacts he and his wife had been studying, but in the heat of the moment, revulsion and fury made it easy for him to raise the rifle and take aim. It was just that in that moment, while his finger tightened on the trigger, the thing's form shifted and for a second it wore Nancy's face.
He supposed that he collapsed in shock, or something equally dramatic; he was not given to dramatics, not given to displays of emotion, but after all the situation was extraordinary. Whatever his response, moments passed in which the creature stole away, and he did not see where it went. As he pulled himself to his feet to retrieve his wife's body, there was only sick numbness and the knowledge that a necessary task must be performed. They had retrieved so much from the planet's dry soil; now he would be putting something back. Finding and destroying the monster that had killed his wife could wait; in retrospect, she had probably been as good as dead before he ever found her.
Crater worked. It was, after all, what he was on M-113 to do, so he dug and catalogued and repaired and interpreted, just as he had always done. If the work went more slowly now that he was without help, or if, sometimes, he would find himself falling into listless periods that lasted for hours, no-one could have blamed him. He supposed that he would have gone on like that forever, with periods of lucidity growing fewer and shorter as despondency claimed him, if it weren't for the footprints. Scuffed and spatulate, they jolted him at last out of his stunned inertia. Footprints--the creature, surely, for he had seen no other sign of life but his and Nancy's on the planet until that very moment. The thing had been roughly humanoid, had crouched on two feet. Yes. Now it was here, it had tracked him here, maybe fascinated or hungry or hateful. It had killed Nancy, and now it had returned for him.
He stopped digging and started tracking. Just as with the weapons training, the Federation made sure its archaeologists had basic survival skills; no point in educating a scientist and dumping him nearly alone, untrained, on a distant world. That sort of thing was a drain on the Federation coffers, and (he supposed) its brain-trust. So Crater tracked, but the rocky terrain made it easy for the creature to avoid leaving an unbroken trail, while the desert wind eradicated the footprints soon enough anyway. Once home, he took to hyperalertness, nerves straining with the need to catch the creature during one of its visits. With discipline and the assistance of stimulants, he could stay awake around the clock--for a little while. Eventually he would falter with weariness, and when he awoke, fresh footprints would appear again, near the compound. How the monster knew when Crater slept, he did not know, and as the fruitless hunt went on, the tracks Crater saw upon waking crept gradually nearer his home.
One morning, when Crater awoke to find the prints closer than they'd ever been, he saw that they ceased being wide and flat, and displayed instead the curved slimness of a woman's foot.
Soon he didn't have to track it. Soon it appeared to him openly, at dusk, at the edge of the ruins. It looked like Nancy. It continued to look like Nancy no matter how long he stared. He was not surprised. He picked up the day's finds, and when he found them unwieldy when added to his notes and his case of tools--he had been almost happy that day, even forgetting the creature for a little while in the exhilaration of finding a new cache of artifacts--the thing, which had drawn quite near, silently assisted him. When he turned for the compound--for home--it fell into step just behind.
He supposed it was cruel, living this way, but he couldn't bring himself to stop. He had Nancy again, or something very like Nancy, and if Nancy's face sometimes became unreadable, if Nancy's voice spoke of memories Nancy never had, he could let it pass. What the creature felt, he didn't know. It told him it was happy--told him that it loved him, wanted to be near him always, would never hurt him, but Crater remembered the way it crouched over the first Nancy, the real one, and pulled her body's salts out through her skin until she died. At this he would become savage, tell himself that the creature chose this path when it took Nancy from him, when it came back to his camp again and again until it could resonate to his own memories of his dead wife. Then he would busy himself with work, determined not to consider what it was like to wear a face that belonged to someone else, to live someone else's fantasy, to be unable even to communicate with one's spouse--he supposed it was his spouse now, that it was all things to him now--without assuming a form alien to it. He had never asked the creature how it felt about this. He never would.