If you really want to scare the kiddies, consider an Anna Wintour costume on Saturday.
Chances are you already have a floral sheath and oversized sunglasses somewhere.
After that, just find some faux fur and pearls (real or also faux), and pick out an impeccably bobbed wig. Most importantly, remember to look bored and unsatisfied all night long. But don't try the accent unless you can really pull it off.
The bonus: Everything here (save the cheap wig) is real-life appropriate, and you can make use of it in your regular wardrobe rotation - wear the floral dress with opaque tights and booties, and pair the faux fur with skinny jeans and one of fall's many shoe trends post-Halloween.
We're not quite sure how to slut-ify an Anna Wintour outfit, but we're pretty sure someone somewhere will try this weekend. If you see her, please send photos.