People stay in a house where they start to act like the last person who used their room
|Main character's name is Adam, but you may add as many characters you want, can focus on any character at any time.|
Ms. Sterious is the nice woman in charge of the dorm. As her name implies, shes very mysterious, though no one ever seems to notice what word her name sounds like. Another peculiar thing about her is that despite running the dorm, she is rarely ever seen, and that unless she is around, everyone seems to forget that she exists.
The first room that a person opens the door to, you will feel compelled to just use it, regardless of what it looks like.
Each day, they will slowly start to act more and more like the person the room belonged to, regarless of whether the current occupant and the previous one are of different genders. This happens very gradually and slowly, so don't make the changes happen to rapidly.
As days go by, the stuff in the room will slowly start to change as if they were meant for the new occupant, but they will not notice. Ex: Clothes will start to alter in size to fit the occupant of the room.
If the room belonged to multiple people(like parents, or twins, etc), then they will feel compelled to share the room with someone else, and will invite someone to share with them, who will accept the offer.
If the the room belonged to people who were together, such as married, they will ask a member of the opposite sex who they have invited to share your large room with. Ex: If a guy picks a room for married parents, the girl he invites can be a girlfriend, a girl he has a crush, or just a friend. Same rules apply, with the character starting to act like the person whose stuff they touch first, with their roommate acting like their partner.
If the occupants were twins, they will invite someone depending on the gender of the previous occupants. If both were the same gender, they will invite a member of the same gender, and if they were different genders, they will invite someone of an opposite sex. If not twins, they will invite anyone. Same rules apply, with the character starting to act like the person whose stuff they touch first, with their roommate acting like their partner.
Relationships between the occupants will start to mirror those whose rooms they use. Ex: Two people who use the rooms of a brother and sister who never got along will start to not get along themselves.
No one will be aware of the changes that happen to them. Same goes for the other occupants of the dorm, and even those who don't stay there. Everything will seem perfectly normal about what happens.
For Adam at least, always leave at least a "Something else" option before he picks a room. Leave many different possibilities open. It was a large extended family, so their were many brothers, sisters, parents, aunts, uncles, cousins, etc staying there, so there are plenty of options. Even the ones that have already been done can be used again if you want.
Be creative with the guidlines I have provided.
No physical transformations. Only mental.
No killing off characters
No skipping ahead days
No ending the story
And most importantly, have fun!