The Leviathan

In 2196, the Interstellar Exploration Vessel Leviathan was mankind’s first manned interstellar vehicle ever built. A collaboration between several of the planet’s most powerful space agencies, including - but not limited to - NASA, SpaceX, JAXA, and the ESA, the Leviathan was four square miles long and laid deep in low Earth orbit. Assembled in orbit and equipped with a magnetic ion fusion drive which produced a great amount of velocity and used up very little fuel, a rotating ring-shaped habitat that spun to provide gravity for its many inhabitants, and enough food and water to last centuries provided by a vast greenhouse equipped for microgravity, which was stowed deep inside the vessel, this marvel of human achievement was built to take man to places he could not.
But on its maiden voyage to explore Alpha Centauri - the Sol system’s nearest star system, Earth mysteriously lost all forms of contact with the massive spacecraft past the Oort cloud, and the Leviathan’s crew, which was of 2,500 cryogenically frozen astronauts and five unfrozen commanders, somehow dropped to zero in that same time.
The Leviathan never even returned.
== - - - - - - The Failed Mission - - - - - ==
Oh, Christ. 
I didn’t realize it until it was too late. The crew of the Leviathan, our biggest landmark in exploration, it’s gone… Six hundred billion dollars spent on this giant starship, all… dead. 
My team was sent on a mission to find out what happened to the Leviathan, and our vessel, the ISEV Asimov cruised briskly towards one of the derelict Leviathan’s hybrid airlock/docking ports, and as we used the spacecraft’s RCS (reaction control system) to slow down and prepare for docking, the Asimov’s AI exclaimed;
“SIGNS OF LIFE DETECTED. GENETIC CODE - INDETERMINATE.”
We had not expected a response like that. The Leviathan was drained of its atmosphere and every life form inside had died from oxygen deprivation. But how was life thriving inside of its otherwise now-uninhabitable interior?
I had to investigate this so-called “life,” so we approached the airlock, entered it and attempted to open the inside door. But something was holding it together, and it seemed alive as well. Our scientist, Margret, had a remotely detonated handheld explosive used for emergencies only, so we blew up the airlock’s inner door.
The eight of us readied ourselves as best as we could, and as we entered the titanic spacecraft, at first it was completely dark and all we could hear was a soft, slimy noise of something squelching. But as we activated our EVA suit headlights, we were greeted by an unbelievable sight.
Every square centimeter of the spacecraft’s inside was covered in living biomass. It recoiled and pulsated at every stimulus, and spread tendrils like mold to places it could not touch. Eyes, teeth, hair, and twitching, lifeless limbs sprouted from random places in the fleshy ground, and there were patches of glowing abscesses of random sizes which lit up the dark interior and often burst rhythmically, spraying a floating cloud of pus, only to rapidly regrow back.
“Holy mother of Hell,” was my only response.
It was then we heard an eerie, gurgling moan course throughout the vessel’s vacant inside, and even though our headlights could not make out the shape of the source very well, it was clearly humanoid and it looked like a crew member of the Leviathan. My fellow combat specialist readied a gun, and then I realized it was no crew member.
"...ggGRrrRAAaaAAaAAaAAaaaaAAaAAAWWwwWWwRRRrrRLLllLL!!!"
The sound of the gun loading must have startled it, and with a blood-curdling snarl, the beast jumped through the micro-G environment and flashed out a set of serrated claws and countless rows of grinding teeth, and caught one of my team’s members with incredible accuracy and tore him to pieces, drips of his blood and chunks of his flesh drifting through the airless environment.
The sound of his death alerted more mutants, which all were unique from one another. One horrifically malformed, S-shaped body with just a few limbs in place of a head and mouths in place of feet, a giant cluster of eyes with thin tentacles, what appeared to be a giant mouth crawling on its elongated teeth and filled with hundreds more, a cloud-like mass of arteries, a spider-like form made of a pair of limbs and thousands more came after us.
We were prepared to shoot down these monsters. All of us beamed most of the mutants into oblivion but they were persistent. Within minutes all of the mutants had vanquished several of my team and there were only three of us left.
I then attempted to use a bomb to destroy all the mutants, but it was no use. We learned that the hard way, as something even more terrible than all the mutants surrounding us immediately appeared.
The largest mutant of them all - about 100 feet across - soon tumbled into view. It looked like an amoeba of multicolored flesh but with randomly thick and/or thin arteries for pseudopods, and a gigantic, throbbing eye at its center, glazed-out and unblinking. We fired all we could at the abomination but we ran out - it was too resilient, and then it was at this time I knew we had to use a bomb.
I tossed the explosive into what appeared to be a mouth and it detonated inside the monster.
The beast simply exploded into a cloud of blood and bits of viscera, staining the site of its untimely fate with its remains. But by then it was too late - more mutants surrounded us at breakneck speed, and they immediately tore us apart just like my late teammate.
We would never return home, just like the Leviathan.
And none of us will be remembered as humans ever again, either...
Category:Space
Category:Weird
Category:Lovecraftian
Category:Beings
Category:Dismemberment