Published first in Amazing Stories Magazine 1931 February. Digitized by Doug Frizzle from 100 Astounding Little Alien Stories.
A. Hyatt Verrill
He was a magnificent specimen of his kind. Translucent - white, swift in movement, possessing an almost uncanny faculty for discovering his prey, and invariably triumphing over his natural enemies. But his most outstanding feature was his insatiable appetite. He was as merciless and as indiscriminate a killer as a weasel or a ferret; but unlike those wanton destroyers who kill for the mere lust of killing, the Exterminator never wasted his kill. Whatever he fell upon and destroyed was instantly devoured. To have watched him would have been fascinating. A rush, as he hurled himself upon his prey, a brief instant of immobility, of seeming hesitation, a slight tremor of his substance, and all was over; the unfortunate thing that had been moving, unsuspicious of danger, on its accustomed way had vanished completely, and the Exterminator was hurrying off, seeking avidly for another victim. He moved continually in an evenly flowing stream of liquid in absolute darkness. Hence eyes were non-essential, and he was guided entirely by instinct or by nature rather than by faculties such as we know.
He was not alone. Others of his kind were all about and the current was crowded with countless numbers of other organisms; slowly moving roundish things of reddish hue, wiggling tadpole-like creatures, star-shaped bodies; slender, attenuated things like sticks endowed with life; globular creatures; shapeless things constantly altering their form as they moved or rather swam; minute, almost invisible beings; thread-like, serpentine, or eel-like organisms, and countless other forms. Among all these, threading his way in the overcrowding warm current, the Exterminator moved aimlessly, yet ever with one all-consuming purpose - to kill and devour.
By some mysterious, inexplicable means he recognized friends and could unerringly distinguish foes. The reddish multitudes he avoided. He knew they were to remain unmolested and even when, as often happened, he found himself surrounded, hemmed in, almost smothered by hordes of the harmless red things and was jostled by them, he remained unperturbed and made no attempt to injure or devour them. But the others - the writhing, thread-like creatures; the globular, ovoid, angular, radiate and bar-like things; the rapidly wiggling tadpole-like organisms - were different. Among these he wrought rapid and terrible destruction. Yet even here he exhibited a strange discrimination. Some he passed by without offering to harm them, while others he attacked, slaughtered, and devoured with indescribable ferocity. And on every hand others of his kind were doing the same. They were like a horde of ravenous sharks in a sea teeming with mackerel. They seemed obsessed with the one all-consuming desire to destroy, and so successful were they in this that often, for long periods, the ever moving stream in which they dwelt would be totally destitute of their prey.
Still, neither the Exterminator nor his fellows appeared to suffer for lack of sustenance. They were capable of going for long periods without food and they cruised, or rather swam slowly about, apparently as contented as when on a veritable orgy of killing. And even when the current bore no legitimate prey within reach of the Exterminator and his companions, never did they attempt to injure or molest the ever present red forms or the innumerable smaller organisms which they seemed to realize were friends. In fact, had it been possible to have interpreted their sensations, it would have been found that they were far more content, far more satisfied when there were no enemies to kill and devour than when the stream swarmed with their natural prey and there was a ceaseless ferocious urge to kill, kill, kill.
At the latter times the stream in which the Exterminator dwelt became uncomfortably warm, which aroused him and his fellows to renewed activity for a space, but which brought death to many of the savage beings. And always, following these casualties, the hordes of enemies rapidly increased until the Exterminator found it almost impossible to decimate them. At times, too, the stream flowed slowly and weakly and a lethargy came over the Exterminator. Often at such times he floated rather than swam, his strength ebbed, and his lust to kill almost vanished. But always there followed a change. The stream took on a peculiar bitter taste, countless numbers of the Exterminator's foes died and vanished, while the Exterminator himself became endowed with unwonted sudden strength and fell ravenously upon the remaining enemies. At such times, also, the number of his fellows always increased in some mysterious manner, as did the red beings. They seemed to appear from nowhere until the stream was thick with them.
Time did not exist for the Exterminator. He knew nothing of distance, nor of night or day. He was susceptible only to changes of temperature in the stream where he always had dwelt, and to the absence or presence of his natural foes and natural allies. Though he was perhaps aware that the current followed an erratic course, that the stream flowed through seemingly endless tunnels that twisted and turned and branched off in innumerable directions and formed a labyrinth of smaller streams, he knew nothing of their routes, or their sources or limits, but swam, or rather drifted, anywhere and everywhere quite aimlessly. No doubt, somewhere within the hundreds of tunnels, there were others of his kind as large, as powerful, and as insatiable a destroyer as himself. But as he was blind, as he did not possess the sense of hearing or other senses which enabled the higher forms of life to judge of their surroundings, he was quite unaware of such companions near him. And, as it happened, he was the only one of his kind who survived the unwanted event that eventually occurred, and by so doing was worthy of being called the Exterminator.
For an unusually long period the current in the tunnel had been most uncomfortably warm. The stream had teemed with countless numbers of his foes and these, attacking the reddish forms, had decimated them. There had been a woeful decrease in the Exterminator's fellows also, and he and the few survivors had been forced to exert themselves to the utmost to avoid being overwhelmed. Even then the hordes of wiggling, gyrating, darting, weaving enemies seemed to increase faster than they were killed and devoured. It began to look as if their army would be victorious and the Exterminator and his fellows would be vanquished, utterly destroyed, when suddenly the slowly flowing hot stream took on a strange, pungent, acrid taste. Instantly, almost, the temperature decreased, the current increased, and as if exposed to a gas attack, the swarming hosts of innumerable strange forms dwindled. And almost instantly the Exterminator's fellows appeared as if from nowhere and fell ravenously upon their surviving foes. In an amazingly short time the avenging white creatures had practically exterminated their multitudinous enemies. Great numbers of the reddish organisms filled the stream and the Exterminator dashed hither and thither seeking chance survivors of his enemies. In eddies and the smaller tunnels he came upon a few. Almost instantly he dashed at them, destroyed them, swallowed them. Guided by some inexplicable power or force he swept along a tiny tunnel. Before him he was aware of a group of three tiny thread-like things, his deadliest foes—and hurled himself forward in chase. Overtaking one, he was about to seize it when a terrific cataclysm occurred. The wall of the tunnel was split asunder, a great rent appeared, and with a rush like water through an opened sluice-way the enclosed stream poured upward through the opening.
Helpless in the grip of the current, the Exterminator was borne whirling, gyrating madly into the aperture. But his one obsession, an all-consuming desire to kill, overcame all terror, all other sensations. Even as the fluid hurled him onward he seized the wriggling foe so near him and swallowed it alive. At the same instant the remaining two were carried by the rushing current almost within his reach. With a sudden effort he threw himself upon the nearest, and as the thing vanished in his maw, he was borne from eternal darkness into blinding light.
Instantly the current ceased to flow. The liquid became stagnant and the countless red beings surrounding the Exterminator moved feebly, slowly, and gathered in clusters where they clung together as if for mutual support. Somewhere near at hand, the Exterminator sensed the presence of the last surviving member of the trio he had been chasing when the disaster took place. But in the stagnant, thick liquid, obstructed by the red beings, he could not move freely. He struggled, fought to reach this one remaining foe; but in vain. He felt suffocating, becoming weaker and weaker. And he was alone. Of all his comrades, he was the only one that had been carried through the rent in the tunnel that for so long had been his home.
Suddenly he felt himself lifted. Together with a few of the reddish things and a small portion of his native element, he was drawn up. Then, with the others, he was dropped, and as he fell, new life coursed through him, for he realized that his hereditary enemy – that wiggling thread-like thing - was close beside him, that even yet he might fall upon and destroy it.
The next instant some heavy object fell upon him. He was imprisoned there with his archenemy an infinitesimal distance from him, but hopelessly out of reach. A mad desire to wreak vengeance swept over him. He was losing strength rapidly. Already the red beings about him had become inert, motionless. Only he and that thread-like, tiny thing still showed signs of life. And the fluid was rapidly thickening. Suddenly, for a fraction of a second, he felt free, and with a final spasmodic effort he moved, reached the enemy, and, triumphant at the last, became a motionless inert thing.
"Strange!" muttered a human voice as its owner peered through the microscope at the blood drop on the slide under the objective "I could have sworn I caught a glimpse of a bacillus there a moment ago. But there's not a trace of it now."
"That new formula we injected had an almost miraculous effect," observed a second voice. .
"Yes," agreed the first. "The crisis is past and the patient is out of danger. Not a single bacillus in this specimen. I would not have believed it possible.
But neither physician was aware of the part the Exterminator played. To them he was merely a white corpuscle lying dead in the rapidly drying blood drop on the glass-slide.