The first thing I learn about navigating the insides of a monster the size of a mountain is this. The body changes constantly.
The tunnels don't stay the same shape. They don't stay the same color. Sometimes they don't even stay in the same place. It's like walking through the guts of a storm. Literally Guts.
I drag myself forward, one hand pressed to my ribs, the other gripping a broken metal rod I salvaged from the ruins of someone's armor. It's bent, half-melted, and hissing with leftover stomach acid. But right now, it's all I have.
I don't know which direction leads to the heart, only that I need to go deeper. Toward the pulsing vibrations coming from far below.
The tunnels throb around me, carrying tremors through the flesh. They're constant, steady, like the footsteps of a giant. Like a titan moving across the world.
God.
I can feel the monster walking.
Every step echoes through its anatomy, shaking membrane walls, splashing digestive fluid from fleshy canals, vibrating down the length of the creature's frame.
This thing is abnormally big, I've heard of creatures as big as a tower, but this one. This one is bigger and It's outside, somewhere, towering over cities, continents, maybe even oceans. Meanwhile I'm trapped inside, a parasite clawing through its guts.
And it knows.
I can feel it in my bones.
I swear it knows.
...
The next chamber expands suddenly, ballooning outward with a wet fwump.The walls stretch thin like massive red fabric, then collapse inward, blasting me with a hurricane of foul-smelling air.
A lung.
A lung the size of a building.
Every time it inhales, the entire chamber balloons. Every exhale sends hurricane-force pressure through the tunnels. I cling to a ridged cartilage wall as the gale tries to suck me into a spiraling pit that acts like a secondary airway.
"Gagh! Not...dying...here..!"
The lung contracts again, harder, and I lose my grip. I skid across the slick membrane, slamming shoulder-first into a fleshy ridge.
"Ugh!!"
Pain explodes through my side. My vision swims.
I claw at the wall, digging fingers into sticky folds. The wind roars around me.
WHOOMP! WHOOMP! WHOOMP!
The lung begins hyperventilating. Fast, panicked, spasming. The monster feels me crawling through it. It's reacting.
I squeeze myself through a narrow slit in the chamber wall, scraping skin, tearing cloth, feeling my blood smear against the pulsing folds. The passage twists downward into darkness.
The air pressure shifts.
Something is coming.
I feel it before I understand it. A shift in gravity. A lurch, slow but world-shattering.
The monster is… turning?
No. Its whole body is rotating.
A rumbling roar shakes the walls. A roar loud enough to rattle my bones from within. Then the world tilts. Hard.
The entire digestive tract flips sideways.
I'm flung violently down the fleshy tunnel, bouncing like a ragdoll. I smash into bone-like structures, skid across mucous membranes, crash through dangling strings of tendon.
Something sharp tears into my arm-
A flash of heat-
Then numbness.
I don't even realize what happened until I stop rolling, lying on my back on a pulsing, quivering sheet of muscle.
My left arm is gone.
Gone.
Just… gone.
Blood pours out in rhythmic spurts, matching the distant heartbeat. My vision pulses with it. I scream, a raw, broken sound that feels like it tears my throat open.
"NO..! NO NO NO...DAMMIT....!"
I force myself to sit up, wobbling. My breath shudders. The stump burns, then chills, then turns disturbingly numb.
The monster's internal fluids must have cauterized some of it. But not cleanly. Not well.
I'm lightheaded.
My legs tremble.
But the heartbeat… I can hear it and it calls me forward.
I can't stop now.
I won't.
The tunnel widens into a cathedral-like ravine of bone. Rib-like structures curve overhead, each bigger than a tree trunk. The floor is made of layered muscle, twitching and contracting rhythmically. Electric pulses crackle between nerves like arcs of lightning.
This is closer.
Closer to the core.
Every thrum I feel vibrates through the bones. A slow, powerful BOOOM… BOOOM… BOOOM… like distant thunder.
The heart.
I limp across the trench, using the spikes of cartilage for leverage. Lightning-like nerve signals snap across the chamber, nearly knocking me off my feet.
Then a massive contraction nearly crushes me as the ribs pull inward like a vise.
The monster is trying to squeeze me out.
Or kill me outright. But I still have a fight in me left.
I dive through a gap just before the bones slam shut behind me with a wet, thunderous THROOM. I hit the ground hard, teeth rattling. My stump screams. My lungs burn. Oh it burns.
But ahead…
A new tunnel. Wide. Red. Bright.
Lit from within.
When I reached it, I stop breathing.
Not out of awe.
Out of terror.
The chamber is colossal, big enough to house a fortress. The walls are slick, steaming, wet with nutrient-rich blood. And at the center
An enormous heart.
Organic. Red. Shiny like polished enamel. Veins as thick as trees coil around it, pulsing with pressurized blood. Each beat shakes the entire chamber.
BOOM…
The sound vibrates up my legs.
BOOM…
It echoes through my ribs.
BOOM…
It's alive.
Powerfully alive.
The surface is hard, almost crystalline, glossy with a faint metallic sheen. Like something evolved to be protected. Something built to survive.
But it's still a heart.
Still pumping.
Still killable.
I stand in that infernal glow, drenched in blood, some mine, some not, my remaining hand trembling around the twisted metal rod.
My body is half-ruined.
My chances are microscopic.
But I found it.
I found the heart.
And for the first time since waking inside this nightmare…
I feel something close to hope.
Weak. Faint. Shaking.
But hope.