Meet the Impala. As a human. I’m aware of one fic where it was done and they made her a dude and it was wildly ridiculous. I stuck with her being a chick for a couple of reasons. 1) There aren’t a lot of them around on Supernatural. 2) There’s a couple of female archetypes she fit as a car that work ever-so-awesomely if she’s a human. 3) It’ll make Dean and Sam squirm more if she’s a chick.
Don’t worry— I put too much thought into this and have an explanation for how she looks. I specifically looked for a hairstyle popular in the 1960s, considering she’s a 1967 Chevy Impala. It’s stated in the show she was made on the Janesville assembly line in Wisconsin. Janesville is predominantly white in populous, so she’s caucasian. She had a black paintjob, so her hair’s black. The closest you’re going to get to those headlights is really bright hazel eyes or really bright blue eyes. I chose hazel.
That’s pretty much it. Hope you like it.