"I know I wish I was worth my weight in 5kt diamonds," says the stupid jock as you groan.
You are rightfully annoyed and aggressive. Because of this moron, you are stuck as an attractive woman until he stops being your master. Until he finishes up his damn last wish. And it sucks, not only because you were sighing at his ignorance and at how much you want him gone from your life for good, but also because you didn't hear him distinctly enough. Then you'll have to find fast a very relieving way of screwing him over his last wish. The more humiliating, the more satisfying, in your eyes. So, you're about to ask him to repeat himself but stops just in time, struck by an idea. Did he say... Or... Well, his pronunciation wasn't clear and even if you can GUESS ant what he wants, well, you didn't quite hear him. Technically, he COULD have meant... You suddenly know what to do. And will it be as entertaining as satisfying! And interesting too, because you are curious to see how this will happen. And it won't be THAT cruel. Not like making him into a diamond statue as your first reflex would have been. His new fate shall be a lot kinder.
"Coming right up," you smile saucily.
The little jerk laughs, already imagining the riches he'll soon drown in. But as the magic hits him, he looks perplexed at the lack of the mound of diamonds he was expecting.
"Hey! Where are my diamonds?" he protests with an annoying voice.
"Oh, those will come last," you smirk.
The jerk then feels his body changing drastically as he becomes a demon. A female demon, fit to wear the most exquisite sparkling jewellery. He shall be decked in the most delightful diamonds, each worth 5kt and enough to be his own new weight. Veils and jewels and shiny stones as beautiful as can be imagined. Yes, this demon will be leaving a trail of broken hearts. After all, did you hear "diamonds" or "demon"? You couldn't be sure sand had to take a decision, right? Besides, it is one more wish gone for good.