I am the necklace you're wearing, actually.
You blinked a few times in confusion. "Yeah, and my best friend is a talking rock. Who are you really?"
No, for real, Jack. I have no name other than what you give me because all that I am is around your neck. This is just some personification made in a way that only you can see me and communicate with me. I think you would have freaked out even more if I had just materialized out of thin air!
"Can...Can you do that?"
Eventually, she groaned. The truth of the matter is, I'm very weak right now. And, at this moment, projecting myself as a human form into a mirror is all I can really do. You're the first human I've had contact with in...Centuries, at least.
"Centuries? And what do you mean?"
Well, promise you won't freak out. But by wearing me, you're essentially letting me drain your lifeforce a little...That sounds bad, I know! But I'm not an idiot. Sucking you drain would just cause me to spend another century waiting for someone. I'm just taking enough energy from you that a meal could provide.
As if on cue, your stomach let out a growl. You were suddenly incredibly famished as you doubled over and growled up at the girl/amulet/thing.
"I'm really hungry now, so thanks for that," you said between gritted teeth. "I'm going to go eat my burritos now."
No problem! I only made myself known in the mirror so you wouldn't freak out to a voice in your head, but I can keep talking there.
"Wonderful..."
You proceeded to waddle out of the bathroom and down to the kitchen all the while the bubbly voice of the amulet girl whispered in your ear, like she was leaning over your shoulder.
Really, you're lucky you're the one who found me. My last mistress decided to put me to rest after a long and eventful life.
"And what is it you can do, exactly? Besides be an annoying voice in my head?"
Well, pretty much anything if you provided me enough energy. If you had a thought, I could make it happen. You want to be taller? Get me enough energy and I can do it for you. Want to be buffer? Feed me and I'll make it happen. Anything and everything.
"Huh. That would be kind of nice," you said taking a bite of your still cold-in-the-middle lunch. "Wouldn't those require a lot of life energy though? Won't I end up dead?"
That's why you just use someone else's life energy instead. Just by touching them while wearing me, I can sap their life force instead. That way, you don't have to be the one to suffer the consequences. Just think about it! Any wish, any wish at all and I can make it happen! And you don't even have to pay for it!
"No, but someone else does," you said, swallowing your burrito. "Still, I could think of a few things I would want to wish for. Assuming what you're telling me is the truth"
What are they? Tell me and I'll work for a way to make it happen!
You thought for a moment.
"I wish for..."