...you discover a young girl about your age already in the tree house and she was naked. She turns around to look at you and smiles. Something about that smile gives you pause and then the tree house door slams closed behind you making you jump. It was then that the girl said "I've been waiting years for someone to come into this tree house. Now I'll be able to leave."
"Wh-what do you m-m-mean?" you asked really scared.
"Oh I'll just enter your body" the girl said. "Though it will have to be changed to suit me. Now take off those clothes."
You shook your head remembering the last time your dad caught you naked in front of a girl. You were so scared that you wet your diaper again. The girl came toward you saying "It will be easier if you take your clothes off yourself."
You turn around and try to get out of the tree house. Unfortunately the door wouldn't budge. You decide that your best option now is to yell for help. "Mommy! Daddy! Help me please! I'm stuck in the tree house!"
The girl giggles behind you and says "No one can hear you. They don't even know you're gone. We are the only ones in the tree house and it will stay that way."
The girl puts a hand on your shoulder and you jump. In the next second she had yanked off your teeshirt. You were now in your diaper and flip-flops. The girl looked at you, smiled, and said "You like wearing diapers don't you. Well I guess I can live with that."
You back up against the door but there was no place you could go to get away from the girl. Soon she had stripped you of you diaper as well as you flip-flops. Now that you were naked the girl looked at you with a smile on her face. She then placed her left hand on your right shoulder and her right hand on your little penis. She pressed against your penis hard and you felt an odd tingling spread out from there. You could feel your penis getting smaller and the girl's hand pressing closer to your body. Finally she took her hands off of you and the tingling stopped. You could feel your hair tickling your back and it was down to your waist. You looked down and saw that you no longer had a penis. Instead you had a little slit like your sisters did.
You looked up to see the girl changing your clothes. Your teeshirt became a dress, your diaper became a pink diaper, and your flip-flops became girlie. The girl turned back to you and said "Now to enter your body." She came up to you and turned you around. She hugged you from behind and you could feel her body joining with yours. It was a strange feeling. It felt like cold water was being poured into you through your skin. Soon the feeling stopped and you looked around for the girl but she was not in the tree house any more.
"'I'm still here'" you heard the girl say without hearing.
"Where are you?" you asked looking around frantically not noticing that your voice sounded like a girl's now.
"'I'm in you'" the girl said. "'Put you diaper and dress on before my father gets here. If he finds you naked he'll play a bad game with you. I died from the game.'"
You hurried to get you diaper and dress on. You had just finished putting your flip-flops on when you felt something enter the tree house. You quickly left and went back to your room. There was someone in your room when you got back. Who was it though?