Veena, a 19 year old girl

Looking up from your dog host you saw a human girl approach you. Her skin was brown and she had long black hair...her figure was slender and her height was average. She wasn't the most intimidating of hosts nor did she seem very powerful but she was the first human you met and you could change that soon enough. When she picked you up remained in your dog host....animals were one thing when it came to taking over but more intelligent life forms like humans would require more subtler approaches. You wouldn't do it out in the open and risk alerting others so now it was a waiting game.

The human took you home, your host was her pet but suffice to say she was none the visor to you inclusion. Once home you were left alone to wander freely. The human apparently lived by herself from what you saw from your host's memories. That would work well enough for you...less likely to be found before you could properly infect others. As you explored you saw various things amongst the humans home that puzzled you for the time but surely you would learn more once you upgraded.

The sun of this world soon set and shortly after the human had retired to her chambers to rest. This was the perfect time to strike. Using your smaller body you made your way to bedroom where you easily jumped and landed next to her. She didn't seem to mind as her pet had clearly done so before. Nevertheless you waited until she was sleeping before you moved. Once you were sure she had dozed off you began to exist the dog letting your slime erupt out slowly. The dog's body felt limp having been to small to sustain you long term despite you eating for it. It wasn't dead...just ****...the girl hadn't known about the extra energy you had required but that won't be a problem now.

Your slime form while weak was quick. You had crawled over to the girl's sleeping body and she was none the wiser. Inching closer you made contact with her skin before spreading across her entire chest...she groaned a little as you touched her but that soon subsided as your body melted and dissolved into her. Soon you had bonded with her...your new host. It was time to take control of her.

The first order of business was to merge with her nervous system...attaching yourself to very organs that controlled her body. You spread yourself, easily coating her spinal cord and practically incasing her brain. Unfortunately you wouldn't be able to access her memories just yet. Letting some of yourself merge with her mind did allow access but it was not enough...the human brain was far more complex than all the other animals and it would take time to crack. No matter...you always had plan B.

While the brain was waiting to be used you were still able to take control of the body itself and move it as you will, her brain would be sealed until you desire its use. Opening your new eyes, you blinked as you stared at up the ceiling, noticing how this body viewed the world differently. However then came another challenge, as you tried to get up, you found yourself moving rather awkwardly. It was true you controlled your hosts limbs...but coordination...you lacked a lot without the brain. No matter you'd figure it out. Recalling what you had seen from the dog's POV about your host's movements as well as taking a few minutes to test and better control your new limbs....you were soon able to move.
You were by no means able to do easily...and you definitely lacked the grace the girl had prior but you were able to walk properly on two legs as well as stand and sit so that was accomplishment.

Using your new mobility you moved yourself to a nearby mirror to examine yourself. From what memories you could gleam from the surface you were able to grasp some of the basic information your host. Her name was Veena, she was a 19 year old girl. She was currently a student at a university nearby and was now living on her own.

Looking at your appearance, you were plain looking in your host's opinion. From what you could read she felt lacking in various areas of her appearance than some of the others of kind. Tempting as it may be to switch you were not that a symbiote who discard hosts so easily. While yes you may have done so with the animals...they were more transportation...Veena on the hand....she was yours now...and you'd make her superior....a testament to your prowess as a symbiote enhancing her to be the best.

You started working immediately by redistributing the fats in her body. Whatever little fat existed in her body that wasn't needed was immediately moved and repurposed for both her bust and her rear. You took your time sculpting her figure using the mirror to help you view its external appearance. You didn't inflate her small chest too much it was just a medium sized one when you finished. Likewise...you also just made her rare in slightly more plump. It wasn't a drastic change that would make it unbelievable or make others suspicious...but it was enough to find yourself pleased with. Her stomach likewise had been flattened very much giving her a very lovely hour glass figure which she desperately desired.

With all the current work you could do finish, you began to feel up the adjustments you made. Pleasure felt was definitely worth it. As you glanced back at the mirror you saw Veena's face staring back at you...once more taping into her memories you found the minor ones needed. Curling her lips into a smile you leaned forward staring at yourself. "We're definitely going to be a catch...aren't we Veena?" You teased as you tested your new voice you with a little giggle escaping your new throat.

However that smiled soon faded to a small frown as you realized what you needed to do next. Since you still hadn't cracked her brain and still needed to blend in adjust with the world...you would have to relinquish control back to Veena once morning came. Pouting a little you slowly walked back to bed taking in just how much better you were improving as you now walked more graciously and could actually enjoy the sensation each step brought especially when other areas of your body reacted with each step.

Just before you went to sleep though you noticed the little form of Veena's pet still **** on the bed from your previous possessing. Once again you frowned, however this was not from discomfort for you but rather as a reaction from you body itself. It didn't like seeing the dog in such a state; as a symbiote this was nothing new to you...but it was not in your nature to be outright malicious. You symbiotes joined and spread yourself amongst the galaxy enhancing and uniting everyone under your hive mind. You were conquerors but didn't mean you were outright cruel.

You gently picked up the dog in your arms and used you symbiote abilities to transfer some of the nutrients Veena had to help the dog's body repair itself. It wasn't much but he'd live and you'd probably be able to use him another day. With that settled you lay down on bed once more, keeping the dog snuggled next you as you relinquished control to Veena once more. You would now travel as a passenger in her body...slowly assimilating her memories into yourself and learning and adapting this world. Once you understood enough...you'd begin to enhance her and then spread your influence.

The next day Veena work up feeling energized. She stretched her arm feeling herself a lot more loose than before....also...she was very hungry. The girl didn't know why but she certainly felt a lot better now compared to last night. Getting up she began organizing herself for the day...not aware of the alien waiting within her body and observing her.