Shrink Ray

"I wish --" started Sarah. "No! Wait!" blurted out Jon, "I have an idea." "This better be good," said the tiny woman, "Or I've got a few ideas of my own." "Wish for something that we can use to change our sizes," said Jon, "Like a shrink-ray. That shouldn't negate the wish." "Wish for a shrink ray?" glared Sarah, "That's seriously nerdy." "Just give it a try," sighed the larger twin. Sarah clutched the rock in her palm. "I wish we had a shrink ray," she said. Suddenly, there it was, sitting right next to them. A handheld pistol like device with all manner of buttons and settings. Jon, who realistically was the only one who could come close to handling the device, made a grab for it. "Don't try anything funny," said Sarah, "Remember who has the rock."