All sorts of things come in on a space freighter. Even in the old days grocers were always finding twenty-foot pythons curled cozily inside bunches of bananas from South America; and what sort of undesired stowaways do you suppose you get when you have a cargo of tongarus from south Venus, agatized Fyella corymbs from the district around Aphrodition, handpainted lumigraphs on goor fiber made in Marsport prefecture, and golden rhnx jewelry from the canal centers?
George Saunders, supercargo of the S.S. Trito, gave his wife a warm kiss on the cheek. "For Pete's sake," he hissed into her ear, "act like you're glad to see me, can't you? The Old Man's watching us."
Marta Saunders hesitated a moment and then threw Her plump body into her husband's arms. "Oooh, Georgie!" she squealed. "You sweet old thing! It's so wonderful to see you again!"
"That's enough," George rumbled warningly. He was swaying a little from the impact. "Don't want to overdo it. Let's get out of here."
They started over to the parking area of the spaceport, where their 'copter was. "What's the matter?" Marta demanded as soon as they were out of earshot of the ship. "What do you care what the captain thinks about us?"
"Listen, Marta, the old fool's been riding me ever since we left Aphrodition. Says I'm the most incompetent supercargo he's ever had. Just before we docked today, he said he thought he'd take it up with the union. If he does, you know what'll happen. Pynx said the last time that if he got one more complaint about me he'd take the case to the executive board. I'd lose my license, sure."
"Oh." Marta seemed unwillingly impressed. She got an atomizer out of her handcase and began spraying quick-drying cosmi-lac over the skin of her face and neck. "But what happened?" she asked an instant later when the cosmetic had set. "Why's he so down on you?"
For a moment the fine-etched lines of irritation and petulance faded from George Saunders' face, to be replaced by an expression of honest perplexity.
"Marta, I — wait, here's the 'copter. I'll tell you about it after we get in. And for the love of heaven, don't drop any pop bottles out of the window the way you did the last time I was in port. Having the air police after us would be the last straw, as far as my nerves are concerned."
He slid into the driver's seat. Marta got two bottles of pop out of the refrigerator, shoved straws into their necks, pulled a shelf out of the paneling to hold one bottle at a convenient level under George's nose, and began drinking out of the other herself. "Well?" she asked after a couple of swallows.
George drank from his bottle before replying. "It's the darnedest thing. I remember beginning to load number two and three holds at Aphrodition, and I remember telling the longshore leaderman to have the hatch covers put on again when the holds were filled, but there're six or eight hours in there during the loading I don't remember a single thing about. They're totally gone.
"Well, the way the ship handled at the take-off from Aphrodition, the Old Man thought there must be something wrong, and when we were out in space he went in for a look. Wow! I can see, sort of, why he's sore. Those holds look like somebody'd stirred the things in 'em up with a big stick. About a third of the cargo's ruined. The tongarus have leaked all over those blasted lumigraphs, and— Well, the insurance company is going to raise blue murder, and the owners won't like it one little bit." George licked his thin lips.
"What I want to know," he burst out, "is what happened to me? I must have told the longshoremen to load the holds like that, but— When we were two days out of Venus, I asked Sparks (he's had a pre-medical course, and he's saving up the tuition for medical school) to look me over. He gave me all the tests, dozens of them, and finally told me there wasn't a thing wrong with me mentally or physically except that I needed more rest. Rest, bushwah! I've been sleeping ten hours a night, and I wake up tireder than when I went to bed."
Marta studied him. "You do look sort of tired," she observed. "Maybe you need some vitor-ray treatments."
George ignored this comment. "Of course, the Old Man's not such a bad guy," he said. "He never said anything about that time I missed the ship at Marsport."
"You mean that time you were so drunk on soma? One of the times."
George gave an irritated shrug. "Never mind that," he snapped. "I mentioned it because I asked him to have dinner with us on Thursday, the day before we sail, and I want you to have a real old-fashioned home-cooked meal for him. Maybe I can soften him up. Have something nice for him. None of this complete meal stuff out of the freezer—have something good. Out of cans."
"You mean like my canned crab and mushroom casserole?"
"Um-hum. Have that. And what's that dessert you make with the canned peaches and the soma? Peche flambe, or something. He might like that."
George set the 'copter down neatly on the roof of their apartment house. "Remember," he said, "I've got to make a good impression on him. Flatter him as much as you can, but use your head about it. And if you get any kind of a chance to tell him about how reliable I usually am, do it."
The days moved on toward Thursday. George continued to complain of fatigue, and on Tuesday night Marta woke up shrieking with a vague and horrible nightmare, but it was attributed to indigestion; after a dose of antiacid, she went back to sleep. On Wednesday she had her hallucination. She was putting a bunch of old digests and tabloids away in the closet in the living room when she came across the jacket George had used four or five years ago when he went grotch hunting.
"George!" she called. "Oh, George! Can I throw your old gray jacket away? It's full of moth holes."
"What are you yelling at me for?" George asked irritably from behind her. He had been sitting in his study, which was only about five feet distant from the closet, drinking soma. "I'm right here."
Marta came out of the closet and stared at him. One hand went to her heart. The pallor of her heavy, sagging face showed through her thick face lacquer as a muddy gray.
"Wha— I saw you go into the kitchen!" she said. "You were wearing your brown suit. I was looking right at you, and you walked the length of the living room and went into the kitchen and closed the door behind you. That's why I yelled at you. You were wearing your brown suit. You've got the blue one on now. You were wearing your brown suit!"
"Shut up!" George said passionately. "Are you trying to drive me crazy? I've been sitting right here all the time. What do you mean, you saw me walk into the kitchen? You couldn't have. I've been sitting right here all the time."
"But I saw you! You were wearing your brown suit."
"You imagined it!" her husband shrieked at her. "It's your imagination. You shut up. What are you trying to do, get me so nervous the Old Man will think I'm ready for the loony bin? You imagined it!"
Marta looked at him. She had to lick her lips twice before she could answer. "Yes. Yes, of course. That must be it. I imagined it."
George spent the rest of the day drinking soma and holding his hands up before his eyes to see if they had stopped shaking.
Marta got a five-suit deck of cards out of the closet and played solitaire. None of hergames came out, but she was too distraught to realize that she had left two of the cards inside their box.
Surprisingly, both George and Marta slept well. They awakened far more cheerful than they had been the night before. Even their pre-breakfast snapping at each other lacked its usual note of bitter sincerity.
When Marta left the apartment and started out to do her shopping, she was humming under her breath.
The canned crab was easy enough to locate, but she had to go to three stores before she could find the peaches and the mushrooms. She ran them to earth at last in a little grocery on a side street. Just as she was leaving it, her eye caught the flash of a red label on a low shelf near the door and she triumphantly dug out two cans of tomato soup.
"See what I got!" she said, showing her prize to George when she got back home. "I guess I'm lucky or something. It's awfully hard to find."
"Gosh!" George shut off the video to give her his full attention. "That's wonderful. I happen to know the Old Man's crazy about it. His mother used to have it all the time. I wouldn't be a bit surprised if it makes him change his mind completely about going to the union. Marta, you're a smart girl."
Marta spent the rest of the day at the beauty shop, getting her hair re - garnished with galoons and her face set. She wanted to make the best possible impression on the captain. Around five-thirty she began getting dinner — it doesn't take long to open cans — and an hour or so later the Old Man (his name was Kauss) was chiming at the door.
Kauss was definitely stiff at first. He greeted Saunders with resentful formality and gave Marta the merest flash of a smile before his face grew hard again. When the fragrant steam from the tureen of tomato soup Marta was bringing in blew toward him, he relaxed somewhat, and the salad of canned string beans, onions, lettuce and mayonnaise softened him still more.
By the time he had finished two big helpings of Marta's crab casserole, it began to look like the job was saved. He offered George a cigar and began telling him a long story about what the little Martian hostess at the Silver Weetarete had said to him.
Marta went out in the kitchen to fix the peche flambe. She cut sponge cake into neat rounds, spread disks of hard-frozen banana ice cream over them, and crowned the structure on each dessert plate with half of an enormous canned clingstone peach. From a bottle she poured soma carefully over each of the peaches, set a bit of paper to burning by pressing it against the element in the atomic range, and then used the paper to ignite the soma on the peaches.
"George!" she called in the direction of the dining apse. "Oh, George, honey, help me with the plates!"
She heard him come in. She turned at his step, ready to pick up the plates, one in each hand, and give them to him. He was wearing his brown suit.
But— he was wearing the green one today, wasn't he, because it was the best suit he had and he wanted to impress the captain.
His green— his green- George's face slipped down toward the fourth button on his coat. It wavered, solidified, flowed back into place, and then slopped down over his lapels once more. Suddenly it solidified into a sort of tentacle. It came falteringly toward Marta, half-blind, but purposive.
Marta tried to scream. Her throat was too constricted by terror to let out more than a mere thread of sound, but it had carrying power. George and Kauss, out in the dining apse, heard it.
They came running in. Kauss was quickwitted. He picked up one of the plates with the soma burning on it and hurled it straight at the thing that was wearing George's clothes.
There was an explosion, so loud that the plexiglas in the windows bulged outward for a moment, and then a bright, instant column of flame. Then nothing. George's brown suit lay collapsed and empty on the floor.
"It was wearing your suit, George," Marta said hysterically. She was leaning back against the wall, looking faint and sick. "George, it was wearing your suit. Oh, what was it, what was it, anyway?"
Kauss was looking at the debris on the floor. A peculiar expression, half satisfaction, half private insight, hovered around the corners of his lips.
"It was a Mocker, I think," he answered.
"A Mocker? What—?"
"Um-hum. You still find a few of them in the wilder parts of Venus. They're parasite — ah — entities, that feed on the life force, well as the flesh, of human beings. No doubt this one came aboard the ship at Aphrodition, in that consignment of Fyella corymbs They're invisible most of the time, so of course we didn't suspect it."
"But how did it get here?" George demanded. "Why did it pick on Marta as a victim?"
"Well, you see the usual way a Mocker works is to select someone as a host, as a sort of base of operations, and then range out from him whenever it wants to eat. For some reason, whenever it leaves its host, it takes on his features and body and dresses itself in his clothes. That's what happened here. One of the first signs that a Mocker is taking hold is a spell of amnesia, and of course that's what happened to you, Saunders, when we were taking on cargo at Aphrodition, though I didn't realize it at the time.
"A Mocker doesn't usually kill its host directly, but it does draw on his life force to keep itself going, and he usually complains of feeling worn out and tired." Krauss halted.
Marta looked down at her husband's brown suit and the ice cream slowly melting across it "Please, George, pick up that stuff before it ruins your suit completely," she said automatically. And then, to Kauss, "But what happened when you threw the plate at it? What happened? Oh, I was so scared!"
"Yes, the Mockers are terrifying." Kauss agreed. He seemed to square his broad shoulders. "However, at bottom they are unintelligent— look at the stupidity of this one in attacking you when your husband and I were in the next room—and they are really not especially dangerous provided you know the defense against them.
"You see, their body structure, while based on the same elements as our own, involves large quantities of free hydrogen between the body cells. Hydrogen ignites in ordinary air with explosive force — the end product's water — and when I threw that burning stuff at the creature, the hydrogen in its tissues exploded. It blew up. There's probably a good deal more water, vapor in the air in this room than there was before I got rid of the thing."
Kauss cleared his throat. "There's another life form," he said with a faintly professional air, "allied to the Mocker, but with important differences, which is far more dangerous. That's the Stroller."
"The Stroller?" Marta asked. George had put his arm around her; they were not an affectionate couple, but the moment seemed to call for tender demonstration. "Why do they call it that?"
"No one knows, exactly. It seems to come from the creature's own name for itself, for its fondness for taking long, long, walks." Kauss turned the cigar in his mouth. He poked at the suit lying on the floor with the toe of his shoe.
"What does it do?" Marta queried. "Why is it so terribly dangerous?"
"The Stroller doesn't hunt a host, like the Mocker," Kauss replied. "Early in life it takes over the identity of some human being, and it remains indistinguishable from a human being to any usual test. It's so dangerous because there's absolutely no defense against it. No free hydrogen in its tissues. It's indestructible."
"My!" Marta said. "Goodness!"
"It feeds, like the Mocker, on both the flesh and the life force of human beings. Fortunately"— Kauss smiled— "it's very, very rare. There are probably only a few Strollers in the entire solar system, and they reproduce only at widely separated intervals."
Once more Kauss halted and poked absently at the clothing on the floor with the toe of his boot. "There's a peculiarity about their feeding habits," he said. "They'll go for years without feeling any desire to eat their special food, and then something will happen which makes them—greedy, and after that they can't be stopped before they feed."
"Goodness!" Marta said again. She hid a nervous yawn behind her hand. "George, get me a chair, will you? I'd like to sit down." To Kauss, she said, "How did you find out all these things? You must have made quite a study of the subject. Why, I've read several books about Venus, and I listen to all the casts on the video about it, but I never heard either of these creatures mentioned before. It seems to be a sort of hobby of yours."
George pushed a kitchen chair out for her; she sat down with a sigh of relief.
"Not a hobby," Kauss corrected gently. His face began to waver and flow as the Mocker's had gone. Then it snapped back into place.
He licked his lips very delicately.
"You see, I'm a Stroller myself. And, somehow, I'm feeling that I'd like to eat."
Margaret St. Claire is the author of eight novels and over hundred pieces of short fiction. For more on her life and work, please see Andrew Liptak's essay on Kirkus.