Shell Experiment 1

I planned to take Choi Seo-ah back to my apartment and examine her properly. Grabbing her wrist, I pulled her out of the convenience store. Her movements were still awkward. Her legs were stiff like a puppet's, and she stumbled with every step, losing her balance. Her face was blankly empty, but her eyes darted around, trying to take in the surroundings.

"Can't even walk properly? Your cerebellum isn't functioning right."

She just stared blankly into space without responding. The demon possessing Choi Seo-ah's body clearly didn't know how to handle a human form yet.

"Get on my back. I'll carry you."

Of course, she had no idea what that meant. I positioned her ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠against my back and pulled her ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠arms forward. Instead of wrapping around my neck, they dangled limply below my chest. In the end, I grabbed her arms and forced them around my neck. With her on my back, I headed home. Her body heat seeped into my back—warm, human warmth. But whatever was inside was no longer human.

"You're pretty light."

With every step, her C-cup breasts pressed against my back. Soft and yielding. It hit me then that I'd never carried a woman like this before. Supporting her thighs with both hands, I walked on. My fingers sank into the squishy bare flesh peeking from under her micro skirt. Her skin was incredibly smooth. As I moved, my hands naturally slid over her ass. The firm bounce made me grip higher without thinking. Plump ass cheeks overflowed between my fingers.

"Nice body you snagged, demon."

I kneaded her ass as I quickened my pace. Her breath brushed my ear—irregular, occasionally hitching. She hadn't mastered controlling her lung muscles yet.

"Perfect setup for an imprinting experiment."

Imprinting—the phenomenon discovered by Konrad Lorenz—occurs when exposure to a stimulus in early life stages shapes long-term behavioral patterns.

"Most mammals are most sensitive to imprinting within hours of birth."

When a demon possesses a human body, neural plasticity peaks, entering a hypersensitive phase. The brain's neural circuits reorganize around that stimulus.

"For imprinting, stimulating the visual cortex neurons first should help."

I swung her around to my front. She wobbled, but I cradled her face-to-face. Time to imprint my features on Choi Seo-ah.

"This is my voice. Remember it well. Remember my face too. I'm your master."

I kept drilling it into her: I'm your master. Pumping my voice and face into her relentlessly. She might not grasp the words yet, but I repeated "master" over and over. Demons using a human brain were like newborns. Right now, it was probably scanning her hippocampus and cerebellum memories, learning patterns. Reading her desires and instincts.

After the imprint stimulus with my face and voice, I gave the reward: gently rubbing her clit. Her body twitched as pleasure built. The female body was designed this way. Childbirth demands immense pain and sacrifice. Sex delivers ecstasy that erases it all—that's its essence. I linked imprint reinforcement to clit stimulation as reward.

But suddenly, her body tensed slightly. Stress.

"Fuck."

Cortisol during imprinting weakens the effect. Good thing I'd studied behavioral imprinting.

"Ah... Being outside stresses you out, huh? Fine. We'll do it at home."

I halted the imprint reinforcement and hurried home. Once inside, I sat her on the bed. She sat like a doll, back straight but swaying slightly, struggling to balance.

"Time to start the real experiment."

I waved my fingers left and right in front of her eyes. Her gaze followed slowly. Eye movements weren't smooth yet.

"Looks like you still can't access this body's memories."

The demon hadn't reached her hippocampus. Imprinting might even be draining its energy more.

I lightly tapped her cheek. No reaction.

"How about pain response?"

This time, I pinched her arm hard. Her face twisted faintly. The nervous system was working. Sitting face-to-face, I spread my hand wide and raised hers to match.

"Now, copy me. Move your fingers like this."

Inducing mirror neuron synchronization. I folded fingers one by one, waiting for her to follow. She stayed still at first, then her fingers twitched like spider legs—irregular, clumsy.

"Like a bug trying to puppeteer a human body."

I grabbed her jaw and squeezed hard, forcing her mouth open like dosing a dog with pills.

Her mouth gaped wide. I peered inside.

"Salivary glands are secreting fine... Huh. Tongue piercing?"

Typical for a delinquent. Girls do it for extra stimulation when sucking dick.

That sex score can't be right. I set her hand down and unzipped her Adidas tracksuit. Pale skin emerged, faint blue veins visible above her sternum.

"The human body links the nervous, endocrine, and circulatory systems in complex ways. Controlling it all won't be easy for you."

I stripped off the tracksuit and unhooked her bra. Moist, perfectly shaped, soft breasts spilled out. Nipples pinkish.

"Body temperature regulation seems fine..."

I rubbed a nipple lightly with my finger. It hardened instantly. A faint breath escaped her lips.

"Imprinting reinforcement made her sensitive to sexual stimuli. Dopamine reward system intact. Hypothalamus and limbic system must be fine."

I yanked off the micro skirt and panties together. Her pubic area was neatly groomed. Virgin body, but well-maintained. Stroking her thigh made the skin quiver faintly.

"Involuntary muscle response. The body reacts to stimuli."

Fully nude, her pale body was beautiful—balanced proportions, smooth skin, defined lines.

"Now for deeper tests."

"Hah..."

I slid my hand between her legs. Her entrance was already slick. The human body responded regardless of the demon's will.

"Already wet. Human bodies don't lie."

Spreading her legs, her outer labia parted with a wet smack.

"What? You're a virgin."

Choi Seo-ah's clit had a barbell piercing.

"You... had massive sexual cravings but no ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠one to fuck you?"

Honestly, her face wasn't stunning—cute nose and lips, but mismatched features and small eyes didn't scream appeal to guys. Still, pale skin and juicy curves guaranteed a boner. Sex magnet body.

I lightly rubbed her pierced clit. Her pussy slickened quickly. Natural response.

"Lewd demon. Your true nature's showing. I'm your master. Remember that."

I slid a finger in slowly. Plenty wet inside. Curled it to hit her G-spot; her hips bucked slightly.

"Oh, you like that spot."

Her vaginal walls clenched. I rubbed the inner wall with my middle finger, speeding up. Her blank expression shifted—faint pleasure now.

"Hah... hah..."

Faint moans leaked. Not intentional—just disrupted breathing from pleasure. Added a second finger, thumbed her clit. Her body shuddered in spasms. Fingers gripped and released the bedsheet.

"Clit stimulation amplifies it. Body reacts beyond your control. Look at me, Choi Seo-ah! Listen to my voice."

Her pleasure-glazed eyes met mine. Her pussy clamped hard, squirting fluids.

"This is your reward for obeying my command and serving your master."

Orgasm hit. Eyes rolled back, mouth agape drooling.

"This raw physical pleasure processes in the brain's primal areas. Even a demon can't fight the body's response."

Before she recovered, I flipped her prone, ass up, exposing her anus.

"Humans have multiple holes. Let's test this one."

Saliva on her asshole, then a finger in slow. Tight resistance, but it yielded. Her body stiffened. Then a cold clunk against my finger.

"A piercing... in your ass?"

I spread her cheeks wide with a flashlight. Deep inside, a shiny metal ring piercing.

"You got off even shitting? Perverted bitch."

I shook my head at her. Needle marks and bruises on her arm screamed drug addict. But a virgin with this slutty body? Unbelievable.

"Let's poke around."

Finger in slow. Intense pressure. She tensed.

"Euuuh..."

Painful groan. But I kept going, sliding in and out, stretching her. Other hand on her clit. Pain and pleasure mixed; reactions got weird. Writhing in agony yet chasing pleasure with her hips.

"Dual stimulation confuses the body. Human nerves are complex like that."

Finger-fucking her ass, I turned her face ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠to me.

"Two sphincters: outer voluntary, inner autonomic. You can't fully control the inner one."

Deeper thrust; her back arched like a bow. Pain-pleasure mix.

"Euuuh..."

Low moan. No language yet, but primitive vocalization worked. Both hands now: one on pussy and clit, other exploring ass. Triple stim; body reacted harder.

"Pleasure points interconnect. One amps the others."

Her moans grew louder. Body flowed like waves now, not stiff. Demon adapting.

"Ahh... kuh..."

"Look at me, Choi Seo-ah. At your master. Hear my voice."

"This human body betrays your soul. Know how its nerves react?"

Max speed thrusting. Ass muscles spasmed. Body slick with sweat, sheets soaked.

"Look at this perverted slut body. Demon-possessed, still going crazy for pleasure."

Second orgasm: eyes fully rolled, tongue out drooling. Classic ahegao.

"Haaaaah!"

Full-body convulsions. Ass and pussy clenched my fingers. Fluids squirted like a fountain, drenching the bed.

"Oh, squirting already? Adapting fast."

Her body shook through the intense, prolonged climax, then collapsed limp. Linked imprint to reward system.

"Fascinating experiment. Saw how quick you adapt."

I sat her up. Her eyes were different now—demon's spark deep in the darkness, watching.

"Now I'm curious what demon you are. Crawling Head from the floor?"

Grabbed paper and pen from bedside drawer, set before her.

"Can you write?"

She picked up the pen slowly. Awkward grip at first, then proper. Tried scribbling— just lines.

"Fine motor control lacking. Needs more time."

Cleared the paper, stared into her eyes. She recognized me now. Wanted to speak but couldn't control her mouth.

I laid her down, sat in bedside chair observing. Logged observations on research laptop:

Checked my phone. Camera feed from Gangnam department store gate incoming. No unusual activity yet.

"Still quiet."

Glanced back at Choi Seo-ah. She seemed deeply asleep. Demon needed rest too—or maybe shut down consciousness to adapt to the body.