Acctually this is a take off of Scott Jamisons WORST CASE SENARIO.
Here it is the ancient training ground of cursed springs is a strange and
and elusive place over the centuries it's magic has changed the lives of
many.  One day Ranma Soatome train in this sacred and ancient ground, where
their lives are changed forever.  Genma falls into the spring of drowned
panda, and Ranma into the spring of srown girl.  After a few hours of Ranma
chasing her father around the srping the two eventually arrive at the guides
cabin.  There the curse is explained.  The springs of jusenkyo have varied
effects.  The springs where animals drowns turns the victim inrto an animal,
and is reversable with cold water.  unfortunately the springs where any
intelligent creature drowned are different these transformations can never
revers, and the cursed form is unaging until the victim dies of sickness or
a violent death.  This is becasue the Intelligent being who drowned there
had strong wills, and souls.  The trapped spirits forge the unfortunate
bodies of thos who fall in the springs into what the victim would look like
if they were born as the species, gender, ect.. of the creature who drowned
there.  The springs have other effects on the victims as well.  Those
unfortunate enough to fall in to the spring of a souled being are linked to
the spirit world in some unpredictable manner.  From spirit sight:  Seeing
aura's, ansd spirits that normaly invisible to mortals, to the ability to
any number of things you can imagine.  The spings also impart some knoledge
or instincts into the victims.  Animal instincts for genma, feminine for
Ranma, as well as anew fould intrest in any number of things.  You could get
really nasty with it.  The real twist in this story though is that the
letter arrives several days early, and that gives the Tendo's time to
prepare for the guests.  This includes calling Nodoka.  When Ranma and Genma
arrive at the dojo, Nodoko sees Genma and the red haired girl with him.
Knowing somethigs wrong she begins to grill her husband.  He breaks after
only a few minutes telling the tale of jusenkyo.  Ranma is rather unsteady
right now the shock of jusenkyo, and the new thought in her head are giveing
the new girl a lot of trouble.  Genma is not killed.  He is not honorable
enough to deserve it.  Nodoka throws Genma out of the house, and takes asks
the Tendo's to help Ranma adjust to a new life.