Elastigirl

The house was always quietest after three a.m., when the night pressed in on the windows, and the last shreds of the family's daydreams collapsed into uneasy shadows in the hallway. In that hour, the boy padded barefoot down the corridor, guided only by the strange certainty that tonight his sister would not wake. She was a witch—a real one, not the Instagram kind—and that afternoon she had blown up the living room with giddy, manic glee, demonstrating at least six new spells, among which was the ability to stretch and contort her body "like that one superhero, the mom," she bragged, then spent an entire hour poking her fingers through the air vent and snaking them, impossibly, past the dust bunnies on the other side.

She called it "hyperflex." He called it "gross." But he watched anyway, as she twisted and looped her arms into impossible pretzels, wound her torso around the bannister like a silk scarf, and tried, with a sort of fevered physical logic, to see what the absolute limit of her own skin might be. She did not notice his fixation, but it was there, gnawing a small, secret hole inside him, one he had never acknowledged before today.

After her final demonstration—turning her head 360 degrees while eating a Pop-Tart—she crashed in a heap on her bed, face-down, limbs splayed like an exquisite crime scene, still half-wrapped in her own elongated scarf of arm. The boy waited. He did his calculus homework. He watched two episodes of a show he would never admit to liking. Then, when the house was a cathedral of soft snoring and refrigerator hum, he crept to her door and nudged it open.

Her body was slack, her breathing deep and even. She did not respond when he poked her, or when he lifted her left hand and let it fall to the quilt. His own hands trembled—he was not sure from excitement, or fear, or the heady mix of both. He had not planned past this point. But as he looked at the tangle of his sister's body, the idea that had been germinating all day bloomed in him, monstrous and irresistible.

He moved slowly. He eased her hand away from her side, then pressed his own fingers into her skin watch ing it bounce back like a rubber band.

He grabbed her mouth, heart pounding in his chest with fear he’d wake her up. He tugged her jaw down, inch by cautious inch, expecting at any moment for the spell to wear off, for her to snap awake and scream.

He squeezed the roof of her mouth, and found it supple, not hard like his own, almost as though her entire skull had been boiled soft. He could not help himself; he reached up further, pushing fingers past the dental gates of her molars, then his knuckles, then his wrist. It was like plunging his hand into a bowl of mashed potatoes, except that the mashed potatoes were warm and alive and breathing around him. He glanced at her face, expecting some sign of struggle, but there was none; just the soft, even rise and fall of her chest.

He pressed on, emboldened by the lack of resistance, and rotated his hand at the wrist, twisting until it met the contours of her throat and then beyond, until his entire forearm slid into the impossible, yielding canal of her mouth. The skin at the corners of her lips stretched and creaked, but did not tear.

He pulled out his arm and climbed on top of her. Then he started to insert his feet and legs.

He withdrew his arm from her mouth, the warmth of her lips lingering on his skin. Then he clambered up onto the bed, straddling her limp, unresisting form.

The boy undressed and positioned himself at the apex of her head, his feet braced on either side of her pillow, and with a trembling, reverential touch, he began to feed his legs into her mouth.

At first, resistance: her lips were parted only a few centimeters, just enough to reveal the picket-fence of her teeth and a pale, inviting tongue. He pressed the edge of his sock against the gap, felt it catch on an incisor, and then—slowly, steadily—the mouth began to yield. Her jaw creaked open, inch by incremental inch, the crisp snap of cartilage offset by the yielding, organic slip of tissue. The boy shuddered as his toes entered the warmth of her mouth. He could feel her breath, slow and foggy, moving in and out around him.

He bent his knees and fed more of himself in, watching as her jaw, impossibly, kept accommodating, stretching, adapting to his growing demand. The process was oddly sensual, but also grotesque, and he felt the pulse of horror beat alongside the thrum of euphoria deep in his gut.

He paused, half inside his own sister, and felt a lurch of nausea mixed with euphoria. He was committing, he realized, a small act of horror. But also, he was doing what he had dreamed of since the moment he saw her stretch: testing limits, breaking rules, burrowing into the unknowable.

He imagined he would be afraid at this point, but instead there was only a giddy, weightless astonishment. He wriggled his shoulders, and they followed, compressing and bending impossibly around his own flesh.

He leaned in farther, pressing his face against hers so that his nose squashed awkwardly to the side, and, by degrees, he eased his chin past her incisors, cheeks distorting so wide he felt the skin at the corners of his mouth threaten to split. Her jaw expanded in kind, stretching around his skull with a disturbing yet elegant elasticity. He heard, rather than felt, the slick suction as his own face entered her, and for a brief instant he was enveloped in total darkness, the world reduced to the close, wet embrace of his sister's mouth and the faint, persistent hum of her breathing.

He was inside his sister. Completely. He wore her body quite literally like a numb suit.

He rolled her over, the movement unsteady, and sat up. Her hair flopped over her face, a curtain of static electricity and tangles. He batted it away and saw, in the mirror across from the bed, his sister’s reflection: pale, slack-jawed, her nostrils flared in surprise. He opened her mouth and stuck out her tongue. It took real effort, like piloting a marionette with gummy strings.

He tested her fingers, flexing them. He swung her legs over the bed and stood, wobbly, elated, and terrified.

He spun her around in a slow circle and caught her reflection in the mirror again: she was standing, slack-jawed, a dazed automaton, eyelids half-mast, lips parted as if mid-sentence. She was still asleep, after all.

He raised her left hand and watched it shake in the glass, the motion not quite matching his expectation, fingers curling too slow, too wide. He touched her face, pressing at her cheeks, pinching her chin until her mouth puckered like a fish. He traced the ridge of her nose, the softness of her earlobe.

He reached up with trembling hands and cupped her breasts, one in each palm. They were heavier and warmer than he expected, an alien sensation even though he had seen them through t-shirts and bathroom doors his whole life. He squeezed, then pressed, then bounced them against her ribs, grinning at the secret elasticity of flesh. He had never really thought of his sister as a woman before—she was his sister, a nuisance, a freak, a magician—but now, moving inside her, he felt the heat and weight of her.

He hammed it up for the mirror, cocking her hip to the side, twirling a strand of hair, then crossing her arms over her chest and blowing an ironic kiss to her own reflection.

He laughed with his own prepubescent voice. Hell, since his voice hadn’t deepened yet, he kinda sounded like a woman anyway.

It was all a game, a harmless trespass.

And then the body around him started to stir.

He felt it first as a ripple at the base of her spine, an involuntary shiver that ran up through the ribs and made the shoulders twitch. Then the eyelids, heavy and reluctant, began to flutter. He tried to clamp down, to force stillness, but the body responded with a gathering tension, a deep and mounting urge to move, to open, to speak.

Her throat made a sound—half groan, half yawn. Her arms moved, not under his command, but in a jerky, puppet-mastered spasm, and he felt panic surge into his chest. All at once, the warm vessel he had conquered turned against him, the muscles contracting and flexing beyond his control.

She was awake.