Be First in the Universe — Terry Bisson

Twins Todd and Tessa don't always think alike, but there's one thing they both agree on -- Gemini Jack's is their favorite store in the mall. Where else can you find a remote control that works on people, or a mirror that sees 10 minutes into the future? And Jack is even stranger -- he glows in the dark, and gives discounts to Tod and Tessa because they're twins. Then Jack develops an interest in the other set of twins in Tod and Tessa's grade -- nasty Ned and Nancy. They're so mean, even their mother is scared of them. Why would Jack want to meet them?
Tod and Tessa are about to learn what happens when you introduce your worst enemies to the coolest guy in the universe.
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