Kress studied it. It still looked like an insect to his eyes. Barely as long as his fingernail, six-limbed, with six tiny eyes set all around its body. A wicked set of mandibles clacked visibly, while two long, fine antennae wove patterns in the air. Antennae, mandibles, eyes, and legs were sooty black, but the dominant color was the burnt orange of its armor plating. “It's an insect,” Kress repeated.
“It is not an insect,” Wo insisted calmly. “The armored exoskeleton is shed when the sandking grows larger. If it grows larger. In a tank this size, it won't.” She took Kress by the elbow and led him around the tank to the next castle. “Look at the colors here."
He did. They were different. Here the sandkings had bright red armor; antennae, mandibles, eyes, and legs were yellow. Kress glanced across the tank. The denizens of the third live castle were off-white, with red trim. “Hmmm,” he said.
“They war, as I said,” Wo told him. “They even have truces and alliances. It was an alliance that destroyed the fourth castle in this tank. The blacks were getting too numerous, so the others joined forces to destroy them."
Kress remained unconvinced. “Amusing, no doubt. But insects fight wars too."
“Insects do not worship,” Wo said.
“Eh?"
Wo smiled and pointed at the castle. Kress stared. A face had been carved into the wall of the highest tower. He recognized it. It was Jala Wo's face. “How...?"
“I projected a holograph of my face into the tank, kept it there for a few days. The face of god, you see? I feed them; I am always close. The sandkings have a rudimentary psionic sense. Proximity telepathy. They sense me, and worship me by using my face to decorate their buildings. All the castles have them, see.” They did.
On the castle, the face of Jala Wo was serene and peaceful, and very lifelike. Kress marveled at the workmanship. “How do they do it?"
“The foremost legs double as arms. They even have fingers of a sort; three small, flexible tendrils. And they cooperate well, both in building and in battle. Remember, all the mobiles of one color share a single mind."
“Tell me more,” Kress said.
Wo smiled. “The maw lives in the castle. Maw is my name for her. A pun, if you will; the thing is mother and stomach both. Female, large as your fist, immobile. Actually, sandking is a bit of a misnomer. The mobiles are peasants and warriors, the real ruler is a queen. But that analogy is faulty as well. Considered as a whole, each castle is a single hermaphroditic creature."
“What do they eat?"
“The mobiles eat pap—predigested food obtained inside the castle. They get it from the maw after she has worked on it for several days. Their stomachs can't handle anything else, so if the maw dies, they soon die as well. The maw ... the maw eats anything. You'll have no special expense there. Table scraps will do excellently."
“Live food?” Kress asked.
Wo shrugged. “Each maw eats mobiles from the other castles, yes."
“I am intrigued,” he admitted. “If only they weren't so small."
“Yours can be larger. These sandkings are small because their tank is small. They seem to limit their growth to fit available space. If I moved these to a larger tank, they'd start growing again."
“Hmmmm. My piranha tank is twice this size, and vacant. It could be cleaned out, filled with sand...."
“Wo and Shade would take care of the installation. It would be our pleasure."
“Of course,” said Kress, “I would expect four intact castles."
“Certainly,” Wo said.
They began to haggle about the price.
* * * *
Three days later Jala Wo arrived at Simon Kress’ estate, with dormant sandkings and a work crew to take charge of the installation. Wo's assistants were aliens unlike any Kress was familiar with—squat, broad bipeds with four arms and bulging, multifaceted eyes. Their skin was thick and leathery, twisted into horns and spines and protrusions at odd spots upon their bodies. But