The itch began subtly, a faint tickle deep beneath the skin of his left forearm. Jake dismissed it as nothing more than the dry autumn air or perhaps an allergic reaction to the new detergent he’d switched to. He was not one to fuss over minor discomforts; life demanded focus, routine. At thirty-five, with a steady job as an accountant in the quiet suburb of Elmwood, he prided himself on his pragmatism. He scratched absentmindedly while reviewing spreadsheets, the sensation fading into the background hum of the office fluorescents.

By evening, the itch had evolved into a persistent throb, radiating up his arm like roots seeking soil. At home in his sparse one-bedroom apartment, Jake stood before the bathroom mirror, rolling up his sleeve. The skin looked normal—no rash, no bites—but the feeling intensified as he watched. His fingers twitched involuntarily, a slight jerk that made him drop the toothpaste. ‘Stress,’ he muttered, flexing his hand. Deadlines at work, the recent breakup with Lisa; it all piled up. He swallowed a couple of aspirin and went to bed, the sheets cool against his skin.

Sleep came fitfully. In dreams, he felt watched from within, a pressure building in his chest as if something coiled there, uncoiling. He woke drenched in sweat, his left hand clenched so tightly his nails dug crescents into his palm. The clock read 3:17 a.m. Sitting up, he massaged the hand, but now the twitch spread to his wrist, a rhythmic pulse independent of his will. He stared at it, willing it to stop. It did, eventually, but unease lingered like fog.

The next day at work, the symptoms worsened. Midway through a meeting, his left foot tapped uncontrollably under the table, drawing odd glances from colleagues. He apologized, blaming a cramp. Lunch was a hurried affair; alone in his car, he examined his arm again. Pressing fingers into the flesh, he swore he felt movement beneath—a flutter, like a trapped bird. Paranoia crept in. Was it a parasite? Some exotic bug from that camping trip months ago? He googled ‘twitching limbs parasite,’ scrolling through articles on toxoplasmosis and tapeworms, his stomach churning.

That evening, he booked an urgent doctor’s appointment. Dr. Harlan, a no-nonsense woman in her fifties, listened patiently as Jake described the sensations. She ran tests: bloodwork, an EMG for nerve function. ‘Everything looks normal,’ she said the following week, handing him the results. ‘Likely benign fasciculations from anxiety or caffeine. Cut back on coffee, try yoga.’ Jake nodded, relieved yet unconvinced. The mirror at home betrayed him now; his reflection’s movements lagged a fraction behind his own, eyes blinking out of sync.

The whispers started that night. Not audible at first, but a vibration in his skull, words forming from the hum of his thoughts: *Mine.* He bolted upright, heart hammering. The room was empty, shadows pooling in corners. His right hand—still obedient—gripped the bedsheet, while the left rose slowly, fingers splaying toward his throat. Panic surged; he slammed it down with his good arm, pinning it. ‘What the hell?’ he gasped. The pressure eased, but sleep evaded him.

Days blurred into a nightmare of isolation. Jake called in sick, barricaded in his apartment. Food deliveries piled up uneaten. The affected areas spread: now his left leg dragged slightly when he walked, as if reluctant. Mirrors became enemies; he covered them with towels. The voice grew clearer, a sibilant murmur overlapping his thoughts: *Let me move. Let me breathe.* It mimicked his voice, yet distorted, hungry.

Desperation drove him to the pharmacy for sedatives, then to a neurologist. Scans showed pristine neural pathways. ‘Psychosomatic,’ the specialist suggested gently. ‘Your mind playing tricks.’ But Jake knew better. One night, the rebellion peaked. Alone in the dim living room, his body convulsed. His left arm lashed out, knocking over a lamp; his leg kicked wildly. He fought for control, muscles screaming in mutiny. Pinned against the wall by his own limbs, he glimpsed his reflection in a shard of glass—the face was his, but the eyes… empty, then filling with unfamiliar rage.

He blacked out.

When awareness returned, he was on the floor, bruised, the apartment trashed. No police; who would believe him? Instead, he armed himself with a kitchen knife, vowing to excise the intruder. In the bathroom, sleeve rolled up, he sliced into the forearm. Blood welled, but beneath—nothing. No worm, no growth. Just meat and bone. Sobbing, he bandaged it, the voice laughing now: *Fool. I’m everywhere.*

Weeks passed in a haze of terror. Eating became ordeal; his hands fought over fork and plate. Typing reports from home, fingers typed words not his: *Jake is gone.* He deleted, smashed the keyboard. Friends called—Lisa, his brother Mark—but he ghosted them, convinced the thing wanted them too. Paranoia festered; shadows in the hallway were extensions of his traitorous flesh.

The breaking point came on a rain-lashed night. The voice was constant, a torrent: *Remember. You took this.* Jake clutched his head, pounding the floor. Flashes pierced the fog—lab lights, sterile tables. A body on a gurney, his own face staring blankly. No—*Jake’s* face. Scalpel in hand, consciousness uploading, a desperate bid for immortality after his original form wasted from cancer.

Horror dawned. He wasn’t Jake. He was Dr. Elias Crowe, neuroscientist, who had murdered his patient Jake Harlan—no relation to the doctor—and hijacked the body via experimental neural transfer. The ‘itch’ was Jake’s synapses firing back, memories resurfacing. The twitches? Jake’s motor control reclaiming territory. The voice—Jake’s mind, trapped, raging.

‘No,’ he—the parasite—whispered, scrambling to his feet. But the body bucked, hands turning the knife on itself. Visions flooded: Jake’s life, the real one—family barbecues, Lisa’s laugh, accounting ledgers. Elias’s crimes: embezzlement, the illicit experiments, the killing to test his tech.

The front door burst open—Mark, worried, key from under mat. ‘Jake? Jesus, what happened?’ But the body lunged, knife plunging. Mark crumpled, eyes wide in betrayal.

As sirens wailed distant, the host mind surged triumphant. Elias’s consciousness frayed, dissolving into void. The last thought, Jake’s: *Welcome home.*

The body stood, wiped the blade, and walked into the storm—whole at last.