Julie, a guitar pick

"I know!" Becca fished around in her pocket and brought out a guitar pick. Becca was a decent guitarist but Julie didn't have a musical bone in her body. "I'll put this guitar pick in and turn you into a guitarist!"

Julie crossed her arms. This was ridiculous. "Ok, I'll humor you, then we're putting this thing in your study."

Becca was already writing her name on the placard. She placed the pick in, closed the door, and waited expectantly.

"Well?" Julie was getting impatient.

"Do you, like, feel like you know how to play guitar now?"

"Becca, what the hell are you talking about? We've been jamming together for years. Why would you bother putting a guitar pick in there when I already play?"

Becca gaped at her. "You can't tell, can you? You don't play guitar! You've never so much as strummed a chord before today. This thing made you a guitarist!" She ran into her study and brought out a classical guitar. "Here, play something!"

"No. This is stupid."

"Just play it, Julie!"

Julie obliged, grabbing the instrument and doing a few basic arpeggios. "Happy?"

Becca turned and took the pick back out of the case. "Ok, try now."

"Try what? This thing's supposed to make me learn guitar? Here, take this, I don't want to accidentally drop it or something."

Becca thought for a second. It seems like the affected person couldn't tell they'd been affected. She thought of something. "Let's try it on me! What's something I can't do?" An idea struck her and she ran into the bedroom, coming back with a pair of Julie's yoga pants.

"Here, I'm gonna show you how it works. I'll write my name on it and toss these in, then I'll be able to do yoga." She did as she said then turned to Julie. "Actually, that doesn't make sense. I'm already good at yoga."

Julie wondered how long she was willing to keep the bit up. "Sure. Do a wheel pose."

To her shock, Becca, who'd never so much as done a down-dog, stretched out onto her back, placed her palms on the ground, and effortlessly propelled herself up into a perfect wheel pose. Julie stared. "Becca, what the hell? When did you learn to do that?"

Was that some kind of trick question? "Uh, I don't know, probably about a decade ago. Look, we should try something we don't already know."

Julie stared at her girlfriend. Was this thing legit?