"Hi, Robbie!" a girl says, stepping forward. You're surprised to see a girl your age in your dad's basement, and she looks vaguely familiar. As she brushes aside her long brown hair, you recognise her. It's Elizabeth, a girl from school.But Elizabeth is, to put it lightly, massive! She must be at least 20 stone of pure fat. The girl standing in front of you is svelte, with an athletic physique that doesn't show a single shred of body fat. Yet you'd only seen her yesterday. There's no way she could slim up that quickly. There is a strange band of metal around her neck.
"E-Elizabeth? You look-"
"I know, right! And it's all thanks to your father!" You've never seen her this happy before, and she pulls you into a bear hug. "See you at school tomorrow, Robbie!" she says, passing and climbing the stairs.
The workbenches that line your dad's basement lab are given over to dozens of cages. Inside each one, hamsters sprint endlessly in running wheels, each one sporting one of the same metallic collars that Elizabeth was wearing. You dad is leant over one of these cages, unclipping a silvery collar from around one of the hamster's necks. "Ah, Robbie!" he says, seeing you. "Just the man I wanted to see." He grins wildly, as he does when he's completed his latest invention. "Check these out! Bio-transference collars!"
"Huh?" you say. He tosses the metallic ring into your hand.
"They're my latest thing! You're able to transfer biological information between two organisms. Just finished up trying them out on one of your school friends. Try it on!"
Curious, you clip on the collar on. As you do, you feel a rush of energy and a surge of adrenaline, like you're running a race.
"Pretty cool, huh? I gave one to Elizabeth, then synched her up with all these hamsters here while they run. The effects of the exercise are channeled through the collars, allowing Elizabeth to burn off her calories without ever lifting a finger. The animals do all the work, the person wearing the other collar gets all the benefit. Isn't that amazing? And it's not just weight loss. I can program these collars to transfer any quality from one animal to another - height, age, whatever. The possibilities are endless."