You and Sophia woke up at the same time, both sweating, as if you'd just felt a wave of intense heat and pain rush over you. Sophia's petite body lied right before you. The two of you had gone to sleep cuddling, with her being the little spoon, and you, being a head taller than her, as the big spoon. Your relationship was intimate like that. But on nights as hot and humid as these, you decided that some space was appreciated.
...Only to find out that she wouldn't give.
"What's wrong babe? Did you have the same nightmare?" You asked, wondering why she was still pressing herself against you.
Finally, you realized that neither of you budged, because you found that you couldn't.
Sophia tried to move out of the way, attempting to swing her legs over her bed. It was at that moment that you felt as if you lost control over your own legs, and in a reflex, were pulled forward as well.
"Holy shit," your girlfriend muttered. Her eyes ran over her body, and her hands felt over her legs as well. You felt it when she touched the skin. It was an unfamiliar sensation though. No hairs, no blemishes. You wiggled your toes, and Sophia gasped in response.
"This can't be anything but the Fusion Wave Sam," Sophia told you as you stared in wonder at the two of you in front of the mirror.
Just one pair of legs, one that was able to carry both you and Sophia, as you were merged together at the hips. From this angle, it looked like you were standing right behind your girlfriend, yet it was but an optical illusion, one that revealed something a lot more unnatural. You leaned back to watch what you looked from behind. When Sophia had the same idea, she turned the two of you around, so that your ass was visible in the mirror.
Your hips had gotten larger so as to both carry your larger frame, as well as accentuate Sophia's attractive on the front. Your ass had gotten bigger, possibly more cushiony even, perhaps for added comfort when sat down with your girlfriend practically on your lap. Your shared legs stood firm and muscular, yet were clean shaven like Sophia liked them. The size of your feet was somewhere in between that of your own and that of your girlfriend.
"We could've gotten much worse, from what I've heard and seen of the Fusion Wave in other cities." You told Sophia, trying to comfort her, expecting she'd be very unhappy with the change. Her reaction was rather optimistic though.
"Can't you be a bit more optimistic?" She asked you. "We couldn't have gotten it much better, in my opinion."
"You're not weirded out by it?" You look down at her in bewilderment.
"Of course! But experts have estimated that in a couple of years, somewhere about two-thirds of the world population will have fallen victim by the Fusion Wave already, and it's not leaving anytime soon either. We're definitely one of the lucky ones."
She looked up at me, with a smile on her lips. "Think you can hold it out with little old me?"
You hummed. "Kiss kiss," said, receiving a quick peck on your chin. If she was ready, so were you.
You'd have to explore a bit more of your newly shared anatomy though.