As you suddenly realize what a stupid idea it was to eat candy handed out by a dark-robed, mysterious stranger, your entire body begins to tingle.
Your hair increases in mass, but instead of falling down straight it seems to bunch up on either side of your head. At the same time, your entire body shrinks and changes from straight and firm to softly curved, your chest pushing out into two modest-sized breasts, and a far more important change happens below your belt as your face softens, the features changing significantly, and your arms and legs go from thick and sturdy to slender and delicate.
While this is happening, your clothes are changing, your shirt and shorts merging into one piece of clothing, a brassiere forming to support your new breasts as your underwear changes from boxers to plain white panties, fitting snug up against your now-bulgeless personal regions, your gym socks stretching out to calf length and becoming a softer, finer material, crisp and clean white, your shoes shrinking down to fit your now smaller feet, and becoming lovely red slippers in the process. In a matter of moments it's all over, and you rush to a nearby pool to see what's happened.
In a nutshell - you've become a girl. Where once was a young Caucasian male is now a teenage Chinese girl, clothed in a red floral-pattern qipao, her hair arranged in two buns on either side of her head in the classic "ox horns" style. This is you now.
Yep, accepting that candy wasn't the best decision you've ever made.