Aki - The Parasite Host

You enter the school's rooftop, and you see one of your fellow classmates, a girl named Aki, sitting there having her lunch by herself. Her medium length blue hair gently sways in the breeze, as her silver eyes gaze down at her bento box. When you close the door to the roof, she briefly glances up at you, but doesn't seem to pay you much interest. Aki has always come off as being cold and distant - not the type to talk to others much - so this isn't out of the ordinary. You sit down in a comfortable spot on the roof, and begin to unpack your own lunch. But then... you notice something odd... A small, purple worm, only maybe an inch or so in length is squirming up Aki's shoulder. It must have crawled all the way up her body and she hasn't noticed it yet. You wonder if maybe you should say something to her... "Hm? Is there something on my face?" Aki says calmly, but you struggle to find the words to explain the worm, without sounding weird. It crawls up her neck, but she still doesn't notice it. And then... it reaches her ear. For a moment, she begins to raise her hand towards her ear, like she finally notices a weird sensation. But just before she can swat it away... the worm leaps right into her ear canal! "Huh!? What's that!? Something's in my-" She says trying to push her finger into her ear - only serving to push the worm further inside... "Hey! Ow! Ow ow ow!" She cries out, cupping her hand against her ear, dropping her bento box on the floor in front of her. And then... her eyes go wide... and she drops to the ground of the school roof... She begins to convulse violently. Drool pools at the edges of her lips, as she stares blankly at the sky, shaking, trembling, letting out pained gurgling noises. You watch on in horror, unsure of what to do. After a few moments, the seizing stops. Suddenly, she begins to mumble something unintelligible. She then sits up - her wide, glassy eyes staring off into space. Slowly, her words begin to form into something understandable. "...Hu... man.... human... A... ki... Aki. This body... human... Aki... female... student..." she mumbles, as she finally begins to blink a little. She stands up, and just continues to stare off at nothing for a few moments. She then raises her hand in front of her face and wiggles her fingers. "Wow... fingers... I have... fingers... these are... amazing!" she says with a giggle, as a big smile crosses her face. She then turns towards you, her wide, silver eyes locked onto yours, and she begins to walk towards you. "Hello, hi! I am... well... I don't have a name! But this body's name is Aki, so you can call me Aki from now on! You are... You, right? Aki's brain remembers you! We're classmates, right? Oh, I get to go to school! This is so exciting! Oh! I should probably explain what's going on, shouldn't I?" she says as she gets so close to you that you can feel her breath on your face. "My kind are a type of parasite! Usually we end up in... rats and birds and stuff like that, but I'm lucky enough that I got a human body! Isn't this so cool!? You guys have like... fingers and stuff! Look at these things! Aren't they just the most incredible thing ever!?" she says, wiggling her fingers in front of you.