The concept of "being inside" is relative.

  When you enter a room, you are inside four walls. When you enter the Leviathan, you are inside a new geography.

  The Dreadnought shot toward the monster's colossal gills.

  They were vertical slits on the side of the beast's "neck," each the size of a soccer stadium, opening and closing rhythmically.

  The suction current was so strong that Valéria didn't need to accelerate; she had to brake so we wouldn't be crushed against the Branchial Arches—giant comb-like bone structures that filtered whales and ships as if they were plankton.

  "Hold on!" Valéria shouted, fighting the yoke. "We're going through the filter!"

  The truck spun in the turbulence.

  We scraped past a bone tooth the size of a skyscraper. The sound was metal being sanded: SCREEEECH.

  The chitin armor I created held, but cracked.

  And then, we were through.

  The light of the outer ocean vanished.

  We turned on the Ether headlights.

  The beam of light revealed the Inner World.

  It wasn't a wet red tube like a normal animal's esophagus.

  It was a vast bioluminescent cavern, filled with toxic mist and "rivers" of blue blood flowing through translucent channels on the ceiling and floor.

  Smaller parasites—the size of cars—crawled along the flesh walls, cleaning debris.

  [ENVIRONMENTAL ANALYSIS: INTERNAL ATMOSPHERE HIGHLY ACIDIC.]

  [PRESENCE OF MACROSCOPIC ANTIBODIES DETECTED.]

  "Are we in the bloodstream?" asked Luna, looking out the window with fascination and disgust.

  "No," I replied, consulting the bio-scanner. "We are in the lymphatic system. It's the body's sewage system. If we entered the main artery, blood pressure would have crushed the truck instantly.

  "Valéria, follow the lymph flow. It will take us straight to the Central Node. The heart."

  The Dreadnought sailed down the river of yellowish goo.

  The "ground" was soft and pulsating.

  Suddenly, Luna's radar beeped.

  "Movement!" she warned. "White things coming from the walls!"

  They were Giant Leukocytes.

  White cells the size of polar bears, amorphous and gelatinous, detaching from the tissue to attack the foreign body (us).

  They had no eyes, just pseudopods trying to swallow and dissolve the metal.

  "Immune system activated!" Gristle shouted, climbing into the harpoon turret (now sealed and operated remotely). "Take your medicine, ugly!"

  Gristle fired. The bone harpoon pierced the first Leukocyte. The creature popped like a soap bubble full of acid.

  This story is posted elsewhere by the author. Help them out by reading the authentic version.

  But there were hundreds of them. They swarmed the truck, covering the windows with corrosive jelly.

  "Valéria!" I shouted. "Thermal shock! Use the Seraphim cooling system!"

  Valéria pressed a red button on the dashboard.

  Ejector nozzles on the truck's bodywork fired liquid nitrogen (byproduct of the stolen life support system).

  The temperature around the vehicle dropped to -100°C (-148°F) in a second.

  The Leukocytes froze and shattered, falling off the truck like meat hail.

  "Cleanup complete!" Valéria accelerated. "But the nitrogen runs out in ten minutes!"

  We advanced deeper.

  The lymph channel opened into a colossal chamber.

  The Heart.

  It wasn't a heart. It was a Terraforming Factory.

  The central organ pulsed with intense purple light. It didn't just pump blood; it pumped corrupted mana into the ocean outside.

  Connected to the heart were dozens of transparent "eggs"—Leviathan clones in gestation.

  And protecting the heart, floating in the internal vacuum, was the Core of Will.

  A giant black pearl, the size of a house, spinning furiously.

  It emitted a gravitational barrier preventing anything from touching the vital organ.

  "There!" I pointed. "The Black Pearl. It's his decentralized brain. If we destroy that, the Leviathan suffers brain death and the body collapses."

  "How?" Luna asked. "That gravitational barrier crushes anything that gets close. Not even the harpoon gets through."

  "Matter doesn't get through," I agreed, unbuckling my seatbelt. "But Concept does.

  "Remember what we did in the Amazon? We used divine fire to burn hunger.

  "Here, we're going to use his own biology against him."

  I went to the airlock at the rear of the truck.

  "Arthur! What are you going to do?" Valéria shouted.

  "I'm going out," I said, calm. "I'm going to inject my own Parasite into the Pearl.

  "My symbiote is an Adaptive Devourer. If it touches the Pearl, it will try to eat it. And the Pearl will try to eat it.

  "It will create a biological paradox: The Infinite Cancer.

  "His system will collapse trying to decide who eats whom."

  "You're going to die! The pressure out there will turn you into paste!"

  The Parasite covered my entire body. Not just armor, but a hermetic cocoon of dense black chitin. My eyes were covered. My mouth sealed. I became a living obsidian statue.

  [FULL EXPOSURE MODE: ACTIVATED.]

  [ESTIMATED SURVIVAL TIME: 3 MINUTES.]

  "Open the hatch," my voice came muffled over the radio. "And prep the escape. When the Pearl cracks, this beast is going to have the worst seizure in history."

  The hatch opened.

  The pressure hit me like a punch from a god.

  I was thrown into the acidic vacuum of the heart chamber.

  I floated toward the Black Pearl.

  Gravity tried to crush me. I felt my bones snap inside the armor. The Parasite screamed in pain, regenerating tissue faster than gravity could destroy it.

  Heal. Break. Heal. Break.

  I reached the barrier.

  I extended my hand.

  The Black Pearl spun before me, humming with the voice of a thousand dead whales.

  YOU... DO... NOT... BELONG...

  "I am the error in your genetic code," I thought.

  I touched the Pearl's surface.

  I released the Parasite.

  There was no explosion. There was contagion.

  Black veins shot from my hand and spread across the Pearl's smooth, perfect surface, like ink in water.

  The Pearl stopped spinning.

  The purple light flickered. Turned gray.

  The Leviathan's system panicked.

  ERROR. ERROR. AUTO-IMMUNE FAILURE.

  The Pearl began to rot at accelerated speed. The magical cancer I injected multiplied exponentially, consuming the mana sustaining the gravity.

  The barrier fell.

  The Heart was exposed.

  "NOW, VALéRIA!" I screamed over the radio, feeling my consciousness fade. "TORPEDO!"

  The Dreadnought turned. The rear aimed at the exposed Heart.

  Valéria ejected the Refined Ether fuel tank (which we stole from Petrópolis).

  Gristle fired the harpoon, pushing the tank like a missile.

  The tank flew through the space where the barrier had been.

  It hit the pulsating Heart.

  BOOOM.

  It wasn't an explosion of fire. It was an explosion of necrosis.

  The Ether reacted with the Leviathan's blood. The Heart petrified instantly, turning into dead stone.

  The Leviathan screamed.

  The sound came from every wall of flesh. The whole world shook.

  The chamber began to collapse.

  I was thrown away by the shockwave.

  I lost track of where the truck was.

  I was floating in darkness, my suit failing, acid starting to seep in.

  "This is it..." I thought.

  Suddenly, a mechanical arm grabbed me.

  The Dreadnought passed by me, side door open. Gristle hung out, held by Luna, and pulled me inside like a trash bag.

  "The exit!" Valéria shouted, maneuvering the truck amidst the falling organic rubble. "The exit sphincter is closing!"

  "Exit?" I mumbled, lying on the cabin floor. "Through where?"

  "Through the only place you can leave when the beast dies!" Gristle laughed nervously. "Through the intestine!"

  The Dreadnought dove into the dark, fetid tunnel below the heart.

  We sped toward the light (or what we hoped was the light) at the end of the digestive tract.

  The Leviathan was dying. And we were being... evacuated.