The last-named of these activities was what occupied the interests now of a handsome merboy named Sweepea.

Although only four months old, Sweepea was already as big as the average merchild of thirteen years. Physiologically an adolescent, Sweepea was less mature mentally. But even lacking many realtime years of experience, Sweepea possessed a sharp, probing intelligence and common sense-traits engineered into him to aid his survival.

Generally happy and easy-going in his daily dealings with his fellow citizens of the submarine city, Sweepea found his limited world a delightful place.

Of course, the instructions and advice and affection tendered to him by his dear Uncle Thomas had invaluably supplemented his congenital wit and appreciation of life. Uncle Thomass tutoring on matters philosophical and practical had engendered in Sweepea an openness and curiosity about life.

But Uncle Thomas had never yet tutored him in the ways of love. And Sweepea, urged on by deep, newly ascendant longings, was intent on learning.

Dropping down through the twilit waters below the lowest ends of the dangling tentacles, leaving the safety of Scyphozoa City above and behind for his illicit assignation, Sweepea sent out sonar clicks to alert Snagtail of his coming. Arrowing through the water with efficient strokes and kicks of his webbed limbs, Sweepea was soon rewarded with an answer from his potential lover.

The boy could picture Snagtail vividly. A sleek basal dolphinoid body with a corona of lively ultra-sensitive and capable squid arms around the midsection, Snagtail sported a signature notch in his back flipper.

Sweepea had grown up side by side with the splice, and considered the male his best friend. But lately, that friendship had begun to blossom into something else. Something not generally sanctioned between humans and splices in this community.

And as far as Sweepea knew at this moment, he was fully as human as the other mers.

From below Snagtail rushed up, a darker blackness among the dusk, as if to ram into Sweepea, turning aside only at the last second, and coming to a stop beside the boy.

The two communicated in their common language of clicks and whistles, less information-dense than the hyperflexive sign-language employed between humans underwater.

Missed you, said Snagtail.

Missed you too, replied Sweepea.

Want you. Want you now. No more waiting.

But how?

Dont know. Just try.

With some trepidation, Sweepea allowed himself to drift closer to Snagtail, and soon found himself wrapped in a tentacular embrace, his dorsal side pressed into Snagtails ventral side.

And thats when the change commenced.

Never before had such a thing happened in Sweepeas short life.

Great waves of peristalsis traversed Sweepeas body. Internal organs shifted, exterior forms flowed into new configurations. Cradled in the many aims of his friend and lover-to-be, Sweepea found himself morphing in protean fashion, until at last he resembled his partner down to the signature defective fluke.

And resonating in response to some hormonal wavefront from Snagtail, Sweepea had assumed the female gender.

Sweepea could feel Snagtails penis probing for a home. Wrapping her own squid arms around Snagtail, Sweepea accommodated his thrusting.

Beneath Scyphozoa City hanging like a vast gaudy chandelier above them, the two dolphin splices made love.

After they had finished, they separated, drifting in post-coital bliss.

After some time, Snagtail squeaked.

So nice! Do it again!

Sweepea was not quite so enthusiastic. Although she had enjoyed the experience perhaps fully as much as her partner, she was confounded by the easy and speedy alteration of her morphology. Such a thing had never happened to her before-nor to anyone else in her ken. And beyond any explanation of how she had changed hung a more vital question: would she be able to change back to the only other form she had ever known?

There was only one recourse when faced with such a quandary. The same strategy Sweepea had always employed when in doubt.

Go talk to Uncle Thomas.

Snagtail was bumping his snout playfully against Sweepeas midsection. She flicked him away with her tentacles and messaged, No more. Not now. Must talk with Uncle Thomas.

Skipping out on any attempt to cajole her otherwise, Sweepea rocketed off toward Uncle Thomass home.

Coming upon a pod of merpeople, many of whom she recognized, Sweepea instinctively used her tentacles to message hello. But not only did her new limbs fail to accurately mimic the greeting mudra, but the humans completely ignored the anonymous splice in their midst.

Feeling lost and alone, Sweepea hastened toward the one being who might be able to help her.

Uncle Thomas resided in a living purse that clung remora-like to the outer cowl of one enormous jellyfish. The purse had been biofabbed from several different sea creatures-anemones and sea cucumbers among them. Its walls extracted oxygen from the sea and scavenged carbon dioxide from the interior. Homeostatic mechanisms spliced from hot-blooded animals insured that a livable temperature was maintained for its inhabitant Uncle Thomas refused to modify himself for submarine living. He claimed he was too old and set in his ways to make such a stressful adaptation. Consequently, he spent every hour of every day immured in his protective purse. He occupied himself with reading and viewing material downloaded from the ideocosm.

And with raising his protege, Sweepea.

Uncle Thomas had taught an intellectually voracious Sweepea everything the child knew. But the wise old horse had dangled in front of Sweepea the promise of much more knowledge to come, when circumstances demanded or permitted dissemination.

Sweepea hoped that now would qualify as such a time. If not now, when?

At this late hour, Uncle Thomass home was dark. A school of basal angelfish were nibbling at some of the purses exiguous fronds. The fish darted away as Sweepea arrived. She tickled the purses wake-up node and waited.

A pearly light swelled inside the translucent sac. Uncle Thomas was bestirring himself. In a moment, his familiar blocky face appeared at a transparent oval in the mottled wall. Below the window, a set of rubbery green lips formed themselves out of the smartskin, preparatory to issuing dolphin-speak. Uncle Thomass blunt fingers could not manage the hyperflexure mudras.

Who are you? Uncle Thomas asked. What do you want?

Its me, Uncle! Sweepea!

Uncle Thomas did not seem surprised.

Your first change has overtaken you then, my boy. Congratulations! You are coming into your own.

Why? How?

Your body is unique. Your cells are infinitely plastic. And you contain within you a library of forms. The genomes of all the mosaics ever spliced. You can recreate them at will. And other shapes as well.

Then I can go back to what I was?

I believe so ...

Teach me how!

I cant. Youll have to find that knowledge inside yourself somehow.

Uncle Thomas continued to look out the window with earnest sympathy, but offered no further words of encouragement or advice.

For the first time in his life, Sweepea grew angry with his mentor. He tried to scowl, but his cetacean face was unsuited for the expression. So he whipped around, flicking his tail disrespectfully in Uncle Thomass face, and flashed away.

For half the night, hiding among the lower tentacles of Scyphozoa City, Sweepea strained to re-express her old merperson somatype, to no avail. She grew more and more frustrated and angry, emotions which only seemed to interfere with whatever mental discipline might be needed to trigger the transformation.

Sweepea began to blame her current plight on Uncle Thomas and his insistence on living in out-of-the-way Scyphozoa City. Why couldnt they live in a modem megalopolis like Neo Seattle or Punta Arenas? Sweepea had heard many alluring tales of these cities. Surely such hotbeds of civilization would have experts who could help an individual in such a fix? But no, they had to live in a literal backwater like Scyphozoa City! And why?

Uncle Thomas would always reply to such a question with the same answer: You and I have enemies, child. Enemies who force us to inhabit harsh oases where we can remain unknown.

Enemies ... Sweepea would like to meet one of these imaginary foes ...

Filled with self-pity, Sweepea malingered among the writhing, predatory tentacles almost till dawn before a chance meeting solved her problem.

Two merteens dropped slowly down through the waters, tangled in a lusty embrace. Kissing, petting, the boy and girl were oblivious to Sweepeas presence.

Watching as the pair moved more deeply into their loving, Sweepea felt his old male hormones surging, imagining himself in the role of the merboy.

Cells flowed and reconfigured. This time, Sweepea was able to discern and annotate the processes by which his body morphed. Moreover, the set of procedures could apparently be catalogued and invoked as a routine.

Within minutes, he happily inhabited again the amphibious male body he had known for the whole four months of his life.

But now he knew he could change with the proper stimulation.

And sex seemed to be the trigger.

No longer irked at his uncle, Sweepea swam back to Thomass purse.

The interior illumination still leaked from the window around Uncle Thomass vigilant face, and Sweepea realized that his uncle had indeed been worried about him, but determined not to show it, for one reason or another.

Thomass words confirmed this.

Child! Youve mastered the trick!

Yes! Now I can become anything.

And you must. To learn the true meaning of the lives of splices. Assimilating the precious mundane heritage of our kind is to be your education, before we go extinct. That is why your other name is the Teleological Ark.

The Teleological Ark. Suddenly Sweepea felt a new importance suffusing him, a kind of racial manifest destiny.

For the next several weeks, Sweepea experienced scores of different bodies, mimicking all the aquatic splices who lived in Scyphozoa City, as well as any visiting diylanders. So far, sexual desire seemed necessary to launch each change, resulting in frequent couplings-hardly a drawback to his unique course of study. But after a dozen or so encounters of this type, Sweepea began to imagine a day when he would be able to initiate a change at will, without the trigger of lust.

Sweepeas activities, however, brought inevitable notice to the youth and his uncle. A protean splice was unheard of, and visitors to the city invariably carried away news of Sweepeas indiscreet exploits.

One morning Sweepea and Uncle Thomas were conducting a lesson.

This merperson form is not my true form then, in any sense...? Sweepea asked.

Not at all, replied Thomas. I chose it for you via an exterior somatic prompt once I knew this was the place where you would emerge from your egg.

It feels like the real me. Sweepea paused thoughtfully. But then so has everything else!

Good. You should be at home in any shape- A fleeting shadow was all that saved Sweepea from being brutally smashed by a huge object bulleting down from above. As the flicker of shade occluded his sight, a lifetime of underwater play-reflexes caused him to dart out of the line of the attacker.

Turning around to see what had overshot him, Sweepea confronted a monster: human, lion, scorpion, dragon. In the human mouth of the ghastly creature was a rebreather device. A water-jet backpack aided the ungainly but powerful body in its assault.

The lips on Uncle Thomass purse shrilled out, This is the Manticore! He wants only your death! Flee!

Enemies. Perhaps not as imaginary as he had thought.

Diving downward, Sweepea accelerated with all his sinuous strength.

Close behind, the Manticore used his artificial propulsion device awkwardly, but with undeniable results.

He would overtake Sweepea soon.

Unless Sweepea could find someone or something to halt the killer.

Ahead of the fleeing merboy hung a drapery of tentacles. Was it possible that the Manticore was unaware of their danger to non-citizens?

This was Sweepeas only hope.

He reached the curtain of living ropes just ahead of the Manticore, then was through them.

As soon as the Manticore touched the tentacles, the strong whips reacted as if to dumb prey. Unequipped with the biological tags that every citizen of Scyphozoa City relied on to identify oneself as identical to the big jellies, the Manticore registered as no more than a mouthful of protein.

Instantly a hundred nematocysts fired, barbs with attached organic cords piercing the monster, securing him for delivery to the maw of the jellyfish.

The Manticore let out a titanic ocean-muffled roar, losing his rebreather in the process. He began to claw the tentacles and strike them with his own sting.

Sweepea did not stay to watch the struggle, but instead returned to Uncle Thomas.

Uncle Thomas had already detached his quarters from the jellys cowl. The purse hung in peaceful equilibrium.

Quickly! Hold on tight to this skin!

Sweepea obeyed his uncles command. When the boy was secure, Uncle Thomas activated the magneto-hydrodynamic propulsion system wetwared into the purse. The little module jetted off east at high speed, heading for an unknown destination.

As the water rushed past Sweepeas face, he found his mouth tightening into a sour grin.

Whatever came next, he doubted his life would ever be as idyllic as it had been here in the mothering sea.

Twenty years before Sweepeas birth, Mauna Loa had been the Earths biggest active volcano.

Then it got suddenly bigger.

A lot bigger.

Actually the worlds most enormous mountain, with a volume estimated at 10,000 cubic miles, the peak-along with its four sisters-broke the surface of the Pacific to form the island of Hawaii. Its periodic small-scale eruptions throughout human history had all been manageable if inconvenient for the residents of the island.

Until someone dropped a hardened bunker-buster nuke down its throat.