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This story contains pseudo-incest, mff, cuckquean themes, anal, and an invisible shapeshifting pervert.
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"Oh, she seems hot." Mathew heard the feminine monster whisper in his ear, "Do you want me to hold her down while you FUCK her?" She almost shouted out the dirty word with glee.
"Cynthia," Mathew groaned, his fingers running through his amber hair as he tried to concentrate on his work. "I told you, She's my aunt. I've lived with her since I was six. Also, please get out of my house."
"But you can't stop thinking about her butt." She murmured. "I can see it in your brain!"
"I told you to stop reading minds Cynthia!" He growled.
"Who are you talking to in there?" His aunt entered the room again. She had a sisterly energy to her. More of a teasing older sibling than a parent. "Pasta is done by the way. Do you want me to bring it to you?" She put a hand on her hip and leaned on the wall.
"Yes please Aunt Barb."
"You sound tense." He was even more tense when he felt her come up from behind him and massage his broad shoulders. Her breasts pressed against his back. "I think you are working too hard. It's fine if you need to stay with me a few more months. The job market is crazy right now. You should take a break."
Mathew seethed, "Thanks, but this is better than doing nothing."
"Okay." She shrugged, "But I'll be watching TV in the living room if you need me for anything." She sauntered off. Mathew could not resist turning and looking at her body wriggle away. She was awkward, but very attractive.
Cynthia was still by his side. She was squatting wide like a frog, completely unnoticed by Aunt Barb. She hissed, "Now the breasts. You are thinking about those now. Which do you prefer my master?"
Mathew gave a look to the monster hissing in his ear. She was just human enough such that he had first mistaken her for a woman in a slutty halloween costume. But her skin was pale purple and striped with darker violet, her eyes were orange and shaped like an hourglass each. Her teeth were sharp like a sharks and instead of hair she had tentacles writhing about her. She was naked too, with plump orbs at her chest and wide hips that wriggled and writhed like a fish when she got the attention she so craved. "I can change my form to suit your needs." She whispered. "But I feel you already like the way I look right now."
"I told you, I don't want any of that!" He almost shouted. He took a breath to clam down. "Seriously, out of all the girls in town, how come it's some psychic fish slut that takes a liking to me."
"You may call me what you wish, though, Master," her voice was breathy, "To remind you, my real name is," She she said with something between a gurgle and rasp, "Cthikrndia" when she said it he felt a sensation like ice being dropped down the back of his shirt. He shivered.
"Cynthia. Right." Mathew nodded and gulped. He hated it when she talked like that. Sometimes he could fool himself into thinking she was just some cosplaying stalker in body paint. Though, she was a pervert who could read minds and keep herself from being noticed by humans with her mental powers.
"Mathew," she used his name and squirmed, looking away and blushing deep purple across her body, "Whenever I remember how to saved me, my gills flutter-"
"I just saw that something was caught in an old abandoned net." He shrugged.
"It was so cold. And you were late for dinner."
"It wasn't a big deal-"
"I can read your thoughts. It was a very big deal. You ruined your nice clothes. You were scared because you thought I was human."
He wasn't convinced she wasn't human, though, she was a lot more slimy than a human usually is. "Cynthia, I told you to stop reading minds!"
"I can't stop master. Talking is not my nature. I speak and hear with my mind." She said. "Your thoughts are loud." She smiled, her sharp teeth glinting, "And explicit." she shuddered and cackled. "Oh! No! Don't worry my love! I would never hurt you with my teeth!" she reacted to his gut reaction. "I can change them if you wish. I can alter my genetic substructure. In one weeks time my teeth can be more human, like yours." She gave a slutty pout, "Or I could have no teeth. Imagine how it would feel if I pleasured you like that? Hmm? So soft!"
"Cynthia," He announced her name once more, "I have resumes to fill out and send. You are a weird fish lady I met in a river just an hour ago. I get that you feel like you owe me or something, but could you just back the fuck off?"
"I want what is best for you." She gave a more worried pout. "Your aunt is right. You are too stressed. And there is something she can do for you. I would do it myself, but it will take some time before I can mutate into her form-"
"Don't do that!" He begged.
"If you say so." She nodded. "I can instead shift into any other form you wish. I can read deeper into your subconscious to find the type of woman you didn't even know you wanted-"
"No. No thank you." He shook his head. "Just let me be, alright?"
She only gave him two seconds of pause before sighing, "She wants you too." her voice cracked high.
Mathew nearly broke his keyboard. "What?" She looked away. "Is that true?" she was hesitating. "Don't you lie to me Cynthia-"
"It's complicated!" She whined. "You humans are so irrational." She mumbled, "Your minds are like lots of fish! All at once in one body! And whatever fish is in front, they think they are the one fish!" She gargled, "Part of her fantasizes about you, wants you, spies on you." Mathew was stunned. "Most of her doesn't." She admitted. "And if you asked her for sex she'd say no." Mathew sighed. He supposed he already knew that. "But she would regret saying no." She continued. "She feels loyal to her late sister. Sees it as betrayal. But otherwise-"
"Yea, what would mom think?" Mathew chuckled. "Who knows. She knew her better than me."
"I can make her forget after you fuck her." She suggested. "I can pull out the piece of her that wants it, then put it back when you are done with her."
"No." he shook his head.
She frowned with frustration. "Why master? You two humans want to fuck, and there is no rational reason not to!"
"Because free will is important!" Mathew insisted.
"Free will isn't real!" She growled and gurgled. "You no more decide things in your life than a single fish decides where the school swims. The only thing that is real is instinct, and desire."
