In the shop, there is also a blanket different from any other. A special blanket that combines the people underneath it into a single being. It had been used over decades but it never got tattered, torn, dirty and even lose its magic.
The so-called Magic Blanket is used to merge 2 to 3 people who go underneath it into a new person. It balances everything. For example, if a 16 year old skinny teen and his 40 year old chubby father would go under the magic blanket, when they merge, their age and their body weight will even up. Making their fusion an average weighted man who's 28 years old. The new man will gain its own memories, personalities and traits from both the teen and the father combined.
It doesn't limit to people only as well. If a man and a dog is under the magic blanket, it is possible that they'll merge, but since humans are dominant species, their new body will only take form of a human, but will have some dog-like features such as having the same hair color as the dog's fur pattern, or being hairy, or having a werewolf-ish look.
Although, there had been an issue with the blanket. If its the first time the two got merged, their new body will feel aroused and will it uncontrollably jerk off until it cum.
It had been in display at the shop but nobody had ever bought it, not until one came...