Leave her

"I'm sorry, Miku..." You think to yourself. Sacrificing yourself would be stupid. If you picked her up, you would be shot for sure. The important thing now was to get out of here. You could always transform yourself into Alex at a later point in time.

You make a dash for the end of the hallway, but suddenly, you feel a dart in your back.

"Urk!" You exclaim, and you fall straight to the floor. A second and third dart hits your supple buttocks, and your vision fades at a rapid pace.

"We... Were so close..." You think to yourself and you drift off into dreamland.

...

You blink, and look around as you awake. You seem to be in a test chamber of sorts, about the size of a medium sized room. To your left is a large observation window. Alex, is sitting down on a chair with her clipboard in hand. You're strapped into some sort of restraining device. Your face is down near the ground, but your ass is high in the air. You're kneeling, but your legs are supported up in the air slightly above the height of your head. Your limbs are entirely secured, and your buttcheeks are spread apart by some kind of ass-spreading divider. One part pulls on your right cheek while the other pulls on your left, exposing your stretched butthole to anyone nearby.

You also felt different. As you became more awake, you realized it. You were bigger. Much bigger. About 10 feet tall.

"Rise and shine, May!" Called Alex from over the intercom. "I've got a nice surprise for you..."

From behind you, a door opens. In walk two people in hazmat suits, leading Rei along by the arms. She's struggling and screaming, but seems unable to release herself from their grip.

"Let her go!" You yell. Alex ignores you.

"I'm trying something new today, May. You see, I usually allow my experiments to willingly obtain their first prey by increasing their libido to the point they can't resist. But while I was watching Erza devour your friend Noel earlier, I thought to myself. 'What if Noel was digested alive and NEITHER party was willing?' How hot would THAT be?"

Rei is dragged around to your backside and you feel your stomach plummet. She realizes what's about to happen and screams bloody murder. You plead with Alex to stop, but again, she simply turns herself up and ignores you.

"You're my first test subjects, Rei and May. May will be the predator, and Rei will be the prey. May has been genetically modified, while Rei has not. She will be inserted into May's rectum and pushed into her large intestine where she will be converted to feces. After which, she will then be ejected from May's anus once more, recorded and disposed of! Then, maybe we'll modify May to finally receive her mental modifications... Depends on how good the experiment goes. Begin!"

The two coated figures shove Rei face first into your ass. Her muffled screams for help reverberate throughout your buttcheeks. Your anus sticks to her face like a suction cup, slowly sucking her in against your will.

The two hooded figures continue pushing her in. Soon, her entire head is engulfed within your sphincter. You cry out as her flailing legs are raised into the air and the rest of her body is shoved inside.

As her petite feet slide into your anus, Rei comes to rest in your large intestine. Despite your increased size, she still bulges out of your abdomen and you can feel her weighing down on you. She's wriggling and squirming, but appears to be making no traction against your slimy interior. You can feel her feet kick against your skin, but it simply bounces back, keeping her well-locked up inside of you.

The divider releases, and your buttcheeks slap together. The two figures leave through the door.

"I'll be back in about fifty minutes." Says Alex. "Just in time to see ReI excreted."

...

Fifty minutes later, Rei was no longer wriggling and sobbing. She wasn't moving at all, and you felt a great deal of pressure building in your lower abdomen. As soon as Alex returns, she controls your restraining device to put you in a squatting position with your arms behind your head. The divider opens up your buttcheeks once more and you feel an intense pressure in your sphincter.

"Ahh...Hah.... Erhhgh..."

You try to resist doing what Alex wants, but with your ass stretched open, you can't clench your butt, and Rei's remains begin to poke out from between your chubby cheeks.

"Urrr... Urrrhghghh..."

Slowly, a large brown turd in the shape of a woman emerges from your anus. You feel your asshole constrict her soft sludge, contracting her, but keeping her roughly the same shape.

"Nnngh...! AAAAHHH! Aghn..Noooo! Rgghaaaaa...!"

Your anus crushes and squeezes Rei's head, transforming it into a Hershey's kiss shape. It's completely indistinguishable, unlike the rest of her body. She falls from your butt and lands in a kneeling position, her legs getting smashed and reduced to a brown pile by her own weight.

"Huff... huff..." You pant. You're too exhausted to say anything. You've shed so many tears for Rei that you're unable to cry any longer. And yet, the entire experience was very pleasurable. You feel deeply guilty.

Rei is taken away to be disposed of, and the footage of you digesting her is put up online. You receive and injection in your butt and lose your mind to lust. You desperately desire to shove Alex herself in your ass, as well as her subordinates. However, as you are restrained, you are simply thrown into the makeshift dungeon below the labs. A series of unused rooms designed to lure would-be escapees to their demise.

There, you digest all kinds of girls by stuffing them up your rear. Beautiful women of all kinds are reverted to feces and shat out of your anus, their faces crushed beyond recognition by your sphincter. You heartily drop them into the toilet, where they are flushed down the drain and mixed in with the entirety of the factory's waste. Their remains are stirred around and mixed with the shit, piss and cum of hundreds of other women until they become completely indistinguishable from the rest of the sewage.

[ANAL VORE PRED ENDING ACHIEVED]