As Rick and Morty stepped through the portal, they were greeted with the sight of a massive orgy occurring in front of them. The room was a dimly lit by a wall of blue flame running along the walls.
“Well, looks like we made it to the sex dungeon,” said Rick as took a swig of his flask. “Go try to have some fun, Morty.”
“Rick, this feels weird…” Morty whimpered as he walked beside his grandpa.
“Look, Morty, I know this is probably the first time you’ve seen a girl naked, but you gotta get over it someday.”
“No, I mean I feel weird. My skin is crawling,” Morty said as he rubbed his arms, “and I feel dizzy.”
“Oh shit, I know what’s happening. Morty…I think you’re going to turn in to Summer. This dimension already has a version of you in it. In fact, I saw you over at the other side of the room. But Summer doesn’t exist in this dimension, so it’s turning you into your sister to correct itself.”
“What?! I don’t want to be-“ he was cut off as he hunched over in pain. Morty grabbed his sides as his spine began to extend. With a few loud pops, Morty had grown as tall as his older sister.
“Rick! Do something!”
Rick just stared and took another sip from his flask. “Listen Morty, there’s really nothing I can do right now. Come find me in an hour and we can go home. Hopefully you’ll turn back once we’re back in our dimension.”
“Rick!” Morty screamed. As Rick turned and walked away, Morty felt his scalp itch as red hair tumbled down into his face. He began to breathe heavily as his body continued to shift. He looked down at his significantly older body just as his hips began to expand. With another loud crack, his hips burst outwards into child bearing proportions. His now torn clothes began to melt into a revealing lingerie set. He moaned a little as a silk thong wedged its way up his butt, putting pressure on his groin. He reached down to tug at it when his ass suddenly expanded. He grabbed his butt as he felt it fill up in his hand, leaving him with a perfectly shaped ass. For a moment, he actually felt proud of his new ass, but immediately tried to fight off the new thoughts.
“No, I’m not Summer! I’m Morty! I’m Mort…ooohhhhh,” he moaned as his crotch was assaulted with alien pleasures. As his cock transformed into a dripping wet vagina, jolts of pleasure coursed throughout his body. He reached down to touch his member only to find a moist clit instead. He couldn’t resist rubbing it, and as he did so his thighs began to thicken. He moaned more as his body grew older and more feminine. With one hand in his crotch, he instinctively drew his other hand to his chest where small mounds of flesh began to grow. He tweaked his nipples as they grew larger and more sensitive, cooing louder with each touch. Before long, two large breasts had grown from his chest to be cradled by his arm.
“I…I don’t want…oh god!” she screamed as her voice rose a few octaves. Her mind was assaulted with so much ecstasy that Morty couldn’t find the change anymore. Morty’s face grew soft and feminine as it fully transformed into that of his older sister. Her eyes rolled back as the transformation completed itself. Summer opened her eyes and looked over the orgy taking place. In the corner of the room, she spotted this dimension’s Morty. Feeling promiscuous, she decided to go over and show off her assets.