The Succubus Nightmare
Within the phantasmal universe of Jon's dreams, his consciousness began to drift beyond the confines of mere space and time... out there, where age and form have no meaning, and the great and jealous powers beyond the universe lie dreaming infinite things through infinite aeons, Jon heard a call. It was the Stone -- his Stone, granting his Wish -- and it heralded the powers of Creation come back at last to the world of flesh and blood, to reshape Life and Time and all those things, infinitesimal by comparison, with powers too great for mortal comprehension.
He saw it as they grabbed Karyn's breasts. He felt them knead and reshape her sensitive, womanly curves through time and space, watched as they ballooned out from modest unremarkability to huge, bouncy eye candy, and felt them draw the gaze of men and jealousy of women across time, and Karyn's embarrassment hiding them away under old jacket, growing tighter and tighter through her years. Somehow, Jon blushed; they were violating her, helpless as she mortally was, and would not stop until the Stone was satisfied.
When at last time and space were reshaped, and Karyn's new blonde, busty body was released from their grip, many of the powers Cosmic would not leave. Lingering invisibly among the mortals, evil and unfathomable beings as ethereal as the soul wandered among the plane the Stone had called them back to, causing as they went mischief immaterial. One especially jealous spirit would not leave Karyn be; clinging to her huge, soft tits, subtly it began to influence her, changing her mind and spirit to its desired forms, until at last it consumed her. Karyn writhed in blissful orgasmic agonies as it penetrated her deeply and more deeply, until at last her body and soul belonged to it; and Jon lamented, for his friend was gone.
The flesh forgot, and when Jon came back to mortality at last, he was filled with lust for her. So was Sarah, and her boyfriends, and their girlfriends, and Jon's family, and any mortal it fancied to tease, for its beauty was unnatural. Jon felt himself losing his wits and his mind to this thing in Karyn's sexy new body, and the world about him filling with depravity and debauchery caused by lust for this hateful and jealous thing which returned no true love. Karyn's possessor had no benevolent intentions for Jon and his mortal company; but all the same, Jon, dick throbbing for this fiend, wished achingly for her companionship, and the Stone obliged him with powers incomprehensible...
"I... I wish..." Jon muttered, clutching the stone in his sleep. "I wish she was here... with me..."