The following story may contain very light spoilers for Captain Marvel. Nothing too plot-heavy, just be warned.
The thick smell of sweat filled Mathew's lungs as he lay in the dark recesses of someone's boot. It was empty, but the warmth made him believe it wasn't long ago that the owner's footwear was removed. He could hear people outside of the shoe moving around and talking, but that was it... All that was left around him were the massive prints of the owner's toes. The boots were well worn, but the insole wasn't too terribly destroyed. It was well maintained and well cared for from what he could tell. He didn't have the energy to do much exploring throughout his surroundings, but that was alright. He was near the toe section in a relatively safe place at this point so even if the person did come back, he wouldn't die immediately.
Then, the sound of general panic filled the air. He couldn't tell what they were saying, but they left the room in a hurry. They were all masculine sounding, but it was all just mumbles to him right now. Time passed, and the stale sweaty air began to dissipate more and more... Before the sound of bare feet padding toward him echoed through the chamber.
His world shook violently as he was lifted up into the sky with the boots. His 'safe space' beneath the owner's toes in the toe section was threatened as he felt whoever it was begin to don their footwear. His heart pounded, but something told him to stay where he was - even though he had just been tossed to the arch of her shoe. He waited, he watched, and eventually it came. A bare foot slid into the opening, blocking out most of the light as Vers donned her shoe. Her toes came over him, trapping him beneath her as her heel slid down into the footwear. He gasped and quivered as her foot slid forward, dragging him along and into place beneath her toes. The little one couldn't do anything... Her feet were cool, likely from running around barefoot for so long. She was in a hurry though, and immediately the boot began to shake and move.
Running, he tried to keep as still as possible. The cool skin began to warm up with her actions, quickly causing her to sweat... He didn't know what was going on at all as he felt the foot lift off the ground. If he hadn't been so well placed, he likely would have been thrown around with all of her kicks. He assumed they were as such, since when her foot lifted off in a strange way the toes lifted with it and curled together tightly. If he were in there, he would be dead a few times over from the force of her toes grip! Eventually though, he felt...
Stuck?
The sweat had effectively glued him into place in her boot. The little one could do nothing as she ran about before dropping...
Falling... Something was wrong. The darkness wasn't his friend but he could hear the sound of calamity all around whoever she was. She came to an abrupt stop after the sound of more stuff breaking filled his ears. Destruction and chaos, before a momentary bit of calm. Vers stood up, her movements were slower than they were a bit ago... It sounded almost like rubble had fallen all around her. He stayed where he was though, trapped beneath her toes.
Later
Her suit was sealed well enough that Mathew didn't have to worry about the cold reaches of space getting to him quite yet, but his oxygen was running thin. He had been coated in layers upon layers of sweat throughout Captain Marvel's trip on the planet, and now he was unwittingly being towed along with her in space. He whimpered out a little bit, looking up to the toes surrounding him as he felt his lungs begin to struggle. Then, it finally happened. Throughout everything Carol Danvers did, through every fight she had, he never once broke free from his binds. Even when she switched boots, but now... Her toes dug down into the insole, dragging him up from the place where he was. Beads of liquid sweat floated aimlessly around him as the flesh took him into its embrace. He was already on the edge at this point, and when he was pressed directly into her skin - buried deep where he was - he couldn't resist. [REDACTED]...
The pressure quickly increased as her toes squeezed him... Time slowed, everything seemed to slow. His bones broke, his organs slid from his chest as his eyes bulged from his skull. He let out a little, hushed squeak as he died there - a mere annoyance to her. An annoyance she took care of...
Later on when she boarded the ship to relax for a little while, she made her way to a nearby seat to remove her boots... She, like many others, never knew he existed