Dennis observes his twin brother David having an apparent aroused look on his face from seeing George and Derek transform while getting an idea after noticing his Monsterme profile has a link option to David's profile, likely due to them being twins. He sends a link-up request which David accepts, feeling ready to activate his monster transformation as he proceeds to strip down naked. David looks over to Dennis after he also undressed as they both decide to activate their monster tfs at the same time, unaware that Dennis found a fusion option that he secretly turned on. The twin find themselves suddenly slammed together as they merged into one muscular figure from the necks down with their intertwining dicks shrinking into their fused body which grows skin-colored scales with tinges of indigo and red-violet. Within moments, with Dennis as the left head and David as the right, the twins have merged into a single two-headed lizardman with pointy ears, a short stumpy tail, four toes on each foot, and three fingers on each hand. They also have short stumpy spines on their back, brown on the David's side and blue on Dennis's side.
The others looked and admired the new monster whose two heads are checking out their shared body, David having expected him and Dennis to be turned into similar monsters instead of being fused into a single monster. He then looked up to see Dennis and could tell he had a mischievous gleam on his face, narrowing his eyes at his brother as he let out a thunderous laugh. "What did you do Dennis?" "Well, the app has a 'fusion' option for linked accounts, and of course I had to see what it did," Dennis explained while shrugging their left shoulder. "I had no idea that this would happen though. Guess we'll just have to share."
David sighed, "I thought sharing a bedroom was hard enough when we were kids. Now, we have to share a body." Despite his initial discomfort, he was starting to admire their body as he felt much stronger then when he previously transformed while helping the smile that had crossed his face at that moment. "I knew you'd come around." Dennis teased. "Not that either of us really has a choice now," David teased back as the twins fist bump each other in mutual agreement. "Good thing I don't have any brothers." George shook his head. "I couldn't imagine being stuck to someone." "Whatever," Dennis rolled his eyes as did David while they two both say in unison, "You're just jealous that I'm twice the monster you are." Both pressed their clawed hands against their scaled abdomen, sharing a glance at each other over how in-synch they are while laughing about it.