They hit the trail as soon as they could. The unspoken goal of the twins was to get Sophie to the cave without encountering anyone. Her immense stomach was far beyond anything natural. She had tried cloths with limited success. Her shirt was rolled up to just below her breasts, and her jeans were unable to be zipped or button because of the bottom of her round midsection.
She couldn't fight it, her body was moving on its own. Worse, she caught herself admiring the feminized brothers, whose reduced stature had them wearing some of Sophie's clothing (though they had to roll up the jeans significantly as they were half a foot shorter than her now). There was a definite part of her that liked having made femboys out of two very masculine marines. As her body waddled on, she debated if this was some previously unknown facet of herself or if it was from the thing inside her.
Twice they had to pull off into the woods and hid as other hikers approached. Daniel still had her gun, and she was afraid of what he might be compelled to do if they were found.
Given the bulk of her belly, Sophie was amazed she could move at all. As they progressed she found herself feeling stronger and less burdened. Looking at her arms, the dark raised lines had thickened and multiplied. She was getting stronger because it was growing.
Two hours later they departed the main trail. A mile further and they reached the pond.
It was in a deep hollow, clearly the product of a very large sinkhole collapse. Willow trees ringed the perimeter, throwing shade over the waters. Thick layers of pond scum floated on the green water, with a few dead fish bobbing as well. This was not a happy place, and was almost certainly avoided by anyone who knew it.
The boys worked their way along the edge, no longer needing to assist Sophie at all. The goth girl could feel her stomach bloating further, and thickening tendrils moving under her skin. Despite this, she was being moved along as if her belly was an air filled balloon.
They reached the cave, the opening was about six feet around, with water half way up. They waded into the muck and gloom. Sophie realized she could see just fine despite the lack of a light source. The cave interior was one large round flat chamber, 50 feet across and 15 feet tall in the center. The stagnant water was only knee deep once she was past the cave mouth.
Sophie wanted to stop. She needed to stop. The creature inside her was tensing for something, and she didn't want to find out what it would be. Ultimately she was powerless, it was now in control of their body.
When she reached the center, her knees gave out, dropping her forward into the water. Her belly tore down the middle, rubbery black flesh and fluid surging outwards. She felt herself deflating as the creature pulled itself free. Her left arm rippled from within and split apart, revealing more rubbery black tentacles. She felt a pressure building in her head. As the world faded away, her last thought was to wonder why there wasn't any blood.