Turning the tank's stiff valve with a creak, I listen to the gentle hiss of gas and rub my slowly swelling belly, feeling it grow steadily bigger and tighter under my paws. Another twist, gripping and forcefully turning the old, slightly rusty valve, and the hissing picks up a bit in volume and intensity, my belly growing visibly faster, straining my clothes and bulging out of them. Before long, I am quite round in the middle, but tempted to go just a bit further this time around. Holding the gas tank against my big, round body, I grip it and try to twist, try to force the stubborn valve around just a little further, putting all my effort into it as I slowly bloat bigger and rounder. Suddenly, the tank slips in my grip, I fall onto my big, round, puffy butt and the gas tank clatters to the floor some distance away, the sound of the twin impacts accompanied by a rapid rise in the sound of the rushing gas hose. The tank rushes at its full rate, pouring gas into me just as fast as it can, blowing up my figure bigger and bigger, my clothes tear through as I struggle to wobble onto my feet and waddle towards where it landed, my limbs puffed and bloated up a bit too big and tight to move properly, my huge belly and butt getting in the way at every moment and only growing even bigger and more awkward.
I catch sight of you watching. "Help? Please..." I manage to say through puffed up cheeks, as my hugely bloated arms and paws struggle to reach the floor past my huge belly and push off against it. I wobble about helplessly, the fast running tank just out of reach as I grow more and more round, limbs splaying, body rising up around my bloated face, fingers wriggling as they puff up thicker. Before long I am stuck as a nearly immobile balloon, watching you watch me, big, bulging eyes wide in panic as you just stand there, enjoying the show. My huge, bloated feet start sinking into my big round blimp body, my useless hands doing the same, and still you just watch and enjoy seeing me grow helplessly bigger and tighter, almost completely round as my huge, round toes slowly lose touch with the ground and I rise upwards into the air, slowly at first, but faster as I grow bigger and lighter.
Before long, a gigantic round balloon bobs about at the end of the tight hose, the tank still running at full speed, you look up to see my huge, puffy toes just poking out from the tight, spherical blimp, bloated and distorted face barely visible peeking over the top of it. I try to sputter some last desperate plea for help, but my cheeks and lips are far too big and tight and creaking full of gas for me to make any sounds other than the hiss and creak and strain of my growing body. Now huge and tight, I wave around in the slightest breeze above you, and still getting bigger, a larger gust is enough to drag the tank a few inches along the ground, and then again. Before long, it is bouncing lightly along in the wind, and then, slowly, lifts clean off the ground, pulled upwards by my swelling blimp body, if it could ever again be recognised as such at this size and shape. Gradually, I lose all contact with the ground, drifting upwards, the grass and concrete falling away below me, slowly at first, then faster and faster as I rise over the town, up into the sky, higher and higher. Eventually, the tank runs out, but by now that hardly matters, I float freely in the air, amongst the clouds, and still going upwards, towards the upper layers of the atmosphere.
My body bulges even tighter and bloats even more out of shape as the pressure around me drops lower and lower. You watch me rise until only a tiny distant speck remains, before turning and leaving, happy at the show, but I keep going, too tight and full to move an inch, bigger than buildings, bigger than towns I grow, nothing to compare my size to apart from the tiny spot of the empty gas tank nearly lost against my growing bulk as I float up into the vacuum of outer space, helpless to whatever my final fate might be, whether that be to swell infinitely in the empty void of space or to burst apart into scraps in the silent vacuum.