Note: I'm probably not going to finish this story. I might, but I also might not. Just so you're warned.
Sam and Dean were investigating a case of large objects mysteriously going missing. Houses, office buildings, trees, swing sets, just disappearing overnight.
They walked out of the hotel that morning. Dean had the keys in his hand. But when they reached the spot where they'd parked the night before, the Impala was gone. In its place was a girl, about 22, some kind of punk-rocker-biker-goth person.
Sam thought she was creepy.
Dean thought she was cute.
She was actually just sleeping, right in the middle of the parking lot. Sam went to wake her up.
"Excuse me, miss, how did you get here? Do you know what happened to our car?"
"SAM!" she cried gleefully when she opened her eyes.
She got up and gave him a hug.
"You left me alone out here all night! I missed you! I missed you when you went to college too! Please don't leave for that long!"
Sam was creeped out by her clingyness, especially since he'd never seen her before in his life.
"Where's John?" she asked. "I miss him too. He leaves a lot. I miss him, even though I don't think he's a very good driver. At least he's better than-" she stopped suddenly. "Oh. Dean. Hello," she said coldly.
"Hi!" he said, smiling. "I don't know who this girl is," he thought, "or where she came from, but she's female so I'm going to flirt with her because that's what I do."
"What are you doing here? How soon can you leave?" she asked.
Dean was surprised. She seemed to instantly hate him.
Sam interrupted with the obvious question. "Who are you?"
"I think my name is Baby. That's what he always calls me," she said, pointing at Dean.
"Wait. You're the IMPALA?" Sam asked.
"Yes! Impala. That's my name. I'm Impala."
"This is great!" said Dean. "She's a woman. And she's the Impala."
"Did you wish really hard?" Sam asked Dean.
"Shut up, Sam. Baby, Impala, hi, I'm Dean, you know that, of course you know who I am, hi!" He said, taking her hand and helping her up. She looked at him loathingly.