The sea had grown quieter again, the kind of quiet that waits before something happens.

I had been following the broken edge of a vent field for what felt like hours, keeping low to the stone. The warmth beneath me rose and fell in weak pulses, carrying the faint scent of metal and ash. My body had grown heavier with each movement, the thickened scales from the shell prey slowing my turns. The glow from my luminous meals had dimmed, leaving only faint traces along the edge of my fins.

The world felt still. Too still.

Then the current changed.

It came from below, a slow exhale from the vents that carried something different, heat, sharp and sweet, tinged with decay. I tasted it through the gills and froze.

It was not just warmth. It was life, burned and broken open.

I followed it without thinking.

The trench widened into a bowl-shaped hollow, carved from the vent’s collapse. What I saw there stopped me cold.

A field of bodies.

Scores of them. Small fish, grazers, hunters, all crushed and cooked by the vent’s fury. Their scales shimmered faintly with the same metallic dust that coated the rocks. The water around them pulsed with a chemical warmth, the kind that tasted like blood and iron and promise.

The sea had served up a feast.

For a long moment, I hovered at the edge, half in awe, half in dread.

The smell hit first, a hot, mineral tang that burned through my gills. It lit something inside me I had almost forgotten. Hunger. Real, raw hunger, not the measured curiosity of the last few days.

It drowned out reason before I could fight it.

I moved without thought.

My jaw opened, and the current filled with the taste of death. The first mouthful burned like acid, rich and sharp. I swallowed. Heat raced down my throat, filling every hollow place inside me.

The ache that followed was almost divine.

I lunged for the next body. The flesh was soft, falling apart as I bit into it. The water turned cloudy with fragments. I ate faster, driven by something older than thought.

The System stirred.

[Biomass Acquired: +5 Units]

The light flashed and vanished, drowned by the next bite.

Another.

[Biomass Acquired: +6 Units]

Each line felt like a pulse of reward. I didn’t care about the numbers. I only cared about the heat spreading through my limbs, the rush that filled my veins with light.

I tore through the carcasses one after another, stripping meat from bone, crushing shells that once would have resisted me. My scales rang with the sound of it. The warmth grew unbearable, yet I didn’t stop.

Each swallow made me heavier. Stronger. More alive.

More.

That was all I could think.

The System kept pace, each flicker of text like a heartbeat.

[Biomass Acquired: +8 Units]

[Total Biomass: 4.1% to Next Stage]

I ignored the ache building in my jaw. The bones along my sides felt tight, stretched. The glow beneath my scales pulsed erratically. I fed faster to drown it.

The taste of cooked flesh turned sweet. The water around me filled with floating scraps, each one a promise of another small gain. I devoured them all.

Then the pain began.

It started in my spine, a deep pressure that grew until it felt like something inside me was trying to tear free. The heat from the feast burned hotter, too much to contain. I spasmed, striking the stone by accident. My tail cracked against the rock, and the sound rang through the hollow like thunder.

The System reacted at once.

[Warning: Structural Stress Rising]

[Metabolic Load: Critical]

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I barely read it. I couldn’t stop. The bodies around me blurred together. I felt the hunger turn into frenzy again, but now the pleasure was gone. All that remained was compulsion.

I bit into a half-melted grazer, tore it apart, and screamed through the water as another surge hit.

Something inside me shifted.

The bones along my spine lengthened with a grinding sound. My fins tore and reformed, splitting into sharper ridges. Pain rippled through every part of me, clean and bright.

Growth agony.

I had felt smaller changes before, the slow tightening of scales, the warmth of strength, but this was different. This was violence.

Each mouthful now came with agony, not gain. My jaw ached so hard I could barely close it. My sides burned as new bone pushed through skin. I could feel my own structure changing faster than the flesh could knit around it.

I tried to stop. I couldn’t. The smell of the carcasses was everywhere, flooding the gills, choking the senses.

Stop.

The word carried no strength. My body didn’t obey.

I bit another corpse, and the taste sent another wave of pain through my spine. My muscles seized. The world around me flashed white.

[Biomass Acquired: +4 Units]

[Warning: Cellular Integrity Declining]

I screamed again, though no sound came in the water.

The glow beneath my skin flared, wild and uneven. My body twitched with every pulse. I looked down at my fins and saw the edges splitting, the bone beneath them growing faster than the membranes could heal.

The sea around me darkened with my own blood.

Still, I fed.

Not from choice, but because I didn’t know how to stop.

Each new mouthful hit like fire and thunder together. Every nerve burned. Every part of me screamed. I clawed at the stone, scraping scales free, but the pain didn’t lessen.

The System’s messages blurred together in a storm of light.

[Biomass Acquired: +9 Units]

[Morphological Adaptation Triggered]

[Warning: Tissue Instability Rising]

My tail lashed uncontrollably. I crashed against the ridge, scattering bones and debris. The sea shimmered with blood, mine and the feast’s both.

The growth came in waves.

My fins stretched longer, sharper, splitting into ridges edged with bone. My body lengthened, muscles tearing and reforming around new joints. The gills flared wide, forcing water through like bellows.

The agony was endless.

It felt like being devoured from the inside, my own evolution eating me alive.

I tried to back away from the feast, but my body didn’t listen. The hunger still roared, a command louder than pain or fear. I tore at another carcass, shaking, hating the need that drove me.

Each bite brought less relief. The warmth that had once been strength now felt like poison. My scales pulsed with heat, each plate shifting against the next.

The sea grew darker, the vent’s warmth clouding the water in red and gold.

Stop, I begged again, silently. Please stop.

But there was no mercy in the System. No pity in the sea.

Another line cut through my vision, cruel and indifferent.

[Biomass: +11 Units]

[Adaptation Progress: 43%]

[Pain Response Suppression Failing]

I convulsed again, thrashing in the wreckage. Every motion sent knives of pain down my spine. My body was too full, too heavy. Every breath burned.

And then, just as suddenly, the hunger stopped.

It was not peace. It was emptiness.

The craving, the fire, the drive, it all vanished, leaving me hollow.

I hung in the water, trembling, surrounded by the ruin I had made. The carcasses were gone. Only scraps remained, floating like ash in a red current.

My body pulsed weakly, the new ridges along my fins still raw and bleeding. Every small movement sent a wave of pain through me.

I tried to move forward and almost collapsed. The new length of my spine threw off balance. The water no longer obeyed the way it used to.

The current pressed differently now. The shape of me had changed.

I drifted against the stone, gasping, waiting for the ache to settle.

When I looked down at myself, I saw a creature I didn’t recognise. Longer. Thinner. Harder. The glow beneath the scales had dimmed, but the edges of my fins caught what little light remained and turned it to knives.

This was growth. But it did not feel like victory.

It felt like a loss.

The sea’s warmth brushed my skin, and for a moment, it felt like a hand testing the weight of a coin.

The words rose unbidden.

The sea doesn’t give. It trades.

Each strength I had gained had taken something from me. Agility traded for armour. Warmth traded for exhaustion. Hunger traded for pain.

The sea was not a mother. It was a merchant.

And I had paid dearly.

I floated there for a long time, staring into the dim ventlight. The field of corpses had begun to drift apart, carried by the slow turning of the current. The water carried the smell of decay in every direction, spreading my sin through the dark.

Far above, something stirred in answer. A vibration, low and steady. I froze.

Predator.

It had smelled the feast.

The current shifted again, dragging me toward the edge of the trench. I forced my tail to move, ignoring the tearing pain. I needed distance before the shadow arrived.

The new fins worked differently. They caught the current sharply, slicing instead of gliding. I moved faster than before, though every stroke left streaks of blood behind.

The vibration grew louder. The predator was descending.

I darted into a crack between two slabs of stone and pressed myself against the wall. My gills fluttered, trying to stay silent.

The shadow passed overhead. The pressure of its movement made the rock vibrate. I could feel it through my bones.

It lingered above the field, circling. The sound of tearing filled the water as it claimed what little I had left uneaten.

Even monsters fed monsters.

I stayed hidden until the sound faded. When I finally dared to move again, the field below was empty. The sea had cleaned its own wound.

The warmth from the vent began to fade, too. The collapse that had made this grave had sealed its breath again.

I turned away, drifting back into colder water. Every muscle in my body throbbed. The new fins shivered when the current touched them, still raw from birth.

The System finally broke the silence.

[Biomass: +11 Units]

[Morphological Adaptation Pending]

[Warning: Tissue Instability Rising]

The text lingered longer than usual, its pale light reflecting off the stone. I stared at it until it faded.

Morphological adaptation pending. I didn’t know what form that would take. But I knew now that every gain came with pain.

Growth wasn’t a gift. It was a debt.

I let myself drift until the current took me back into open water. The warmth disappeared behind me. The dark stretched ahead, cold and endless, but clear.

The sea hummed quietly around me, the way it always did after feeding. But beneath that hum was something new, an edge, sharp and steady.

It wasn’t the sound of hunger. It was the sound of warning.

I was changing, and the sea was watching.

For the first time, I wondered which one of us would break first.