Karen's heart raced as the new, exotic hormones rushed through her. She felt an agonizing heat coursing from her loins to her brain and back again, filling her with the urge to mate. Her pussy gushed with liquid, and she slid an alien claw between her legs to thumb her exposed and swollen clit.
Pleasure exploded through her mind as she stroked herself, and she threw her head back to let out a wild screech. Her tongue slithered out her mouth like a snaky vine, instinctively coiling around one nipple while she palmed the other, pawing at it with need. She felt so empty!
The orgasm struck and Karen shuddered against the edge of the bathtub, sliding down as her pussy spasmed around her fingers, juice squirting between the digits like a broken faucet. It seemed to go on forever as she found her rhythm, stroking herself to an unending wave of ecstasy. And yet... it wasn't enough.
She groaned and slipped her fingers free of her throbbing womanhood, letting the orgasm ebb. Her body remained maddeningly aroused, like an itch she couldn't scratch. Instinctively, her serpentine tongue slid back into her mouth as she went to suck her fingers clean. As she brought her hand to her face, she realized that it was changing! The scaly chitin regressed back to supple pink skin and her sickle-sharp claws became normal fingernails.
The rest of her seemed to follow, and Karen looked back in the mirror. She looked as she did before, powerful kryptonian muscles and feminine beauty. Her wet blonde hair was slicked down from the water and she had a hungry gleam in her eyes.
"I look good enough to eat." She certainly felt good. It was a little strange, like she'd had this physiology inside her all along, and it took one small catalyst to help it emerge. She wondered why she wasn't scared or confused. Some part of her told her to find the Justice League or go to S.T.A.R. Labs or something... but it didn't hurt to explore, right? She wasn't going to murder anyone. She was still Power Girl, after all. But she was so horny...!
She went to her closet and found her little black dress -- normally she'd wear something more conservative, or her white formal gown, but what felt natural this time was something short and sexy that clung to her curves and showed off her assets. A pair of "fuck-me" pumps and her ensemble was perfect. Karen blew a kiss in the mirror and stroked her flat stomach in anticipation.
***
The club was thumping with heavy music and flashing with light. Power Girl smiled and shivered. She could smell arousal in the air, and this place was thick with it. She waded into the crowd and found herself grinding and twirling to the music. A cute guy who couldn't have been more than twenty "accidentally" bumped into her, but Karen just rolled with it. As she danced with him, she felt the urge to look him over, inside and out with her x-ray vision. Her heart quickened as she realized she could spot no genetic defects.
Karen pulled him into a passionate kiss, cutting off his attempts to be charming. She didn't care what he said. Her body was demanding to be mated!