They'll Swim Free
My name is Kosak 175, of the Sulp Niar Pool. Head biologist in charge of Visser Three's research and development department. Curse the fool. May he die a slow death by Kandrona starvation.
He always made ridiculous demands, but this newest whim of his was particularly foolish. He tasked my colleagues and I with physically modifying mammalian animals into amphibious specimens. Fool. Didn't he realize that one couldn't simply graft gills and webbed-limbs onto animals to modify them?
But he insisted, and my team of biologists was forced to comply with his demands after he morphed a Luminarious Flamus, an electrically-charged beast from Slegabb Five's eighth moon. The morph was a sure sign of his displeasure, and he made sure to incinerate at least one of my scientists, Antar 5983, who was the best Yeerk geneticist we've ever had.
So we started mutating Hork Bajir. First we tried removing their six-chambered hearts and placing the three-chambered heart of the Earth reptile called a crocodile. The heart transplants worked, but the Hork Bajir died when the hearts could not pump blood with sufficient pressure to oxygenate their bodily tissues fully. Twenty Hork Bajir died during that experiment.
We then tried increasing the Hork Bajir's tolerance of lactic acid, thus increasing their ability to respire in an anaerobic state (i.e. without oxygen). The experiment was a success, but the Visser killed two more of my scientists when he learned that the Hork Bajir could only submerge themselves for up to 60 Earth minutes. That was impressive timing for a mutated mammal, but he was still set on amphibious Hork Bajir.
With only three scientists left on my team (myself included), we were running out of manpower and time. So we decided to modify the Hork Bajir in imitation of the Earth's saline water fish. We worked in a frenzy, adding gills, increasing boron content of the Hork Bajirs' bones (their boron bones got more pressure-resistant), growing kilometers of blood capillaries to be added to the lamellae of their new gill-filaments, and even implanting organic valve-symbiotes from Corlana III in their windpipes to allow swallowed water to be channeled through their opercular openings. We practically made our Sstram host bodies cry out a river of ammonia when the experiment succeeded. When our first specimen managed to sty submerged and respire underwater for up to five hours, we started making fifty more.
But the Visser tested the Hork Bajir three Earth weeks before their physical modifications had settled in and healed. They failed, one-by-one. He murdered thirty-eight of them that way, by using them before they had fully adapted to the mutations we had built into them. He ordered us to discard the remaining twelve Hork Bajir, and feed them to the Taxxons. We cried, as we dragged them to the Taxxon Pit one-by-one.
But we didn't kill all of them. No, we secretly kept three of them alive. A male which we had determined to have high potential of fathering a new generation of amphibious Hork Bajir, and two extremely fertile females of breeding age. We released them into the Earth's oceans when they had recovered, and let them go off without a Yeerk in their heads. We didn't want to control them. We wanted our creations to live.
We were overjoyed when the 'tabloids' as humans call their news-updates, showed that the Hork Bajir had successfully started a colony underwater, in the place the humans call the Marianna Trench. We hoped that they would survive till the distant future, when we Yeerks wouldn't be there to use them. We even modified their DNA sequences before releasing them, so that they would have less chances of inbreeding. Their children would be amphibious, not because of mutation but because we changed their DNA. We even made the females' ovum-developing and releasing properties increase, so that they could bear several young at once.
By our calculations, in three Earth months the three Hork Bajir would have had at least eight children, and would die in approximately two years.
Now, as the Visser is traveling under the sea in his ship the Sea Blade, we hope that he dies down there, so that we might live. To one day meet the next generation of our creations.