"I wish that whenever Sarah or Karyn use the personality manipulator, the change that happens is something different from the setting that's selected, but also something that's definitely unwanted." The stone glowed, granting Jon's wish. Unfortunately, what Jon didn't know was that since he had run away, Sarah and Karyn had already used the device again - on Kyla. So if she used the device, then it would work the way it was supposed to. But at the moment, Sarah was the one using it, so for now, whatever happened next was what Jon wanted.
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Back at the mall, Sarah and her two newest friends Karyn and Kyla encountered some losers that needed fixing, not realizing that they would change, but not the way any of them wanted them to.