A multipurpose wish.

I smiled; holding the stone up. "I think I know how to do several things with one wish. And it should provide some insurance against future mistakes."
"How the heck can you do that; Jon?" Karyn shook her head.
"I wish was a shape-shifter; with the knowledge to safely use my new power."
I felt a wave of ... something ... wash over me. It must have happened in an instant; though it felt considerably longer. I looked at Karyn to see her eyes just moving back to me.
"Nothing happened," she said.
"The wish worked." I put the stone back into my pocket; then ran through the new memories I had gained. "Watch this."
I thought 'fox' - and suddenly my skin was crawling. My bones and muscles flowing like honey. I half heard a ripping sound - and then my flesh and bone were solid again. Karyn stared wide eyed for a few seconds; then slumped to the ground without a sound.
I guess the sight of me changing into a fox morph was too much for her. But my new form had excellent tools for waking up someone who had fainted. I knelt down beside her and began licking her face with my long wet tongue. And tickling her cheek with the tip of my bushy tail.
That's not quite right, I thought after a moment. I shifted my tongue to a raspy cat model.
That did the trick; and Karyn slowly opened her eyes. "It really worked?" she asked.
I 'answered' by shifting back to my normal human form. "There are some limits. And it does take a lot of energy." Which fact my stomach was forcefully reminding me of. "Do you want me to wish you the same ability?"