Karyn pressed a button. The Replomat took verbal commands, but the "make me a girl" kit didn't.
A bright green glow covered Jon and he collapsed onto the mat where he was standing. Karyn quickly took the stone from him. Then his flesh began to glow green and slowly mold itself. As Karyn had guessed, it couldn't modify his skeletal structure, so he'd be a narrow-hipped, tall, girl, but everything that they did specify was working. When the glow stopped, Jon was a girl who was brunette and bisexual, as well as matching the other settings. Her clothes hung on her, now ill-fitting.
His (her) eyes opened. Karyn had expected her to grope herself or something but instead she said "You tricked me, Karyn!"
"Oh, come on," she said. "You were asking for it. I mean, you have a magic stone. Which grants wishes. And you got tripped up by a phrase that shows up in wish stories... you needed to learn what a bad idea it is to say "make me a". I've just taught you something that may have saved you. If, that is, you remember this in the future before phrasing anything that way."
"It's a prank," said Jon.
"It's fully reversible," said Karyn. "You just need to wish yourself back." She held up the stone. "I wish you can't for the next hour," she said, and gave him the stone back. "No need to ruin the prank. Anyway, the people in this universe know about their own technology. They know the Replomat does and they know you have one, so they wouldn't find it strange.
"Yes they would," said Jon. "It wouldn't be strange-impossible, but it would be strange-why-would-he-do-that?"
