Back at the McMudd trailer, Fanny left before Bubba and Bertha asked too many questions about who she was and why she was there. Once outside, she wished to know what Sarah had done to Karyn's parents, to see if there was some way of reversing some, most, or hopefully all of the changes to them. Fanny liked how she was and never wanted to be Jon again, but she still wanted to help Karyn get her family back to normal.
After the small rock glowed, she knew what Sarah had done and was already formulating a wish in her mind to counteract the changes that had been made.
Of course, if Karyn's parents did return to normal (or mostly so), then the situation that Sarah (or rather Beaulah, now) found herself in at that moment might completely change, since Karyn's parents probably wouldn't be into perverted sexual activities like that. So it'd be a plus for both Karyn's parents and Sarah ... but Sarah would still be a fat redneck named Beaulah McMudd.
