You were a fluffy little cat, young and curious. You wandered where ever you pleased as you were a stray cat, not tied down to anything but your basic needs: hunting and sleeping. Speaking of:

One day the Winchester brothers, Sam and Dean, were packing up after a hunt. Both were happy it was over and done with as it had been stressful and tiring. You being you. A cat. Saw an opportunity and you snuck into the back seat of the 1967 Chevrolet impala that was owned by Dean Winchester. You, in fact had been walking all day looking for a place to rest and quite frankly, the backseat of a monster hunters comfy classic car didn't seem so bad right now. (Not that you knew it belonged to hunters, you're a cat. All you wanted was somewhere to sleep)

It was quite late in the night. Dean was driving, humming along to whatever classic rock song he had on and Sam was in the passenger seat just staring out of the window tiredly. And then there was you; curled up in the back seat blissfully sleeping away... That was until you awoke and stretched letting out an involuntary squeak. The squeak caught the attention of Dean as he was the more awake of the two Winchesters.

"Sam, Sam, Sammy.." Dean glanced into the backseat but he couldn't see much as he still had to focus on the road. "Sam-"

"What?" Sam asked irritatedly.

"I heard somethin' in the backseat." Dean responded, completely bypassing his younger brothers irritation. Sam lets out a short huff and he turns to look back into the backseat.

"Well... yuh see anythin'?" Dean asked, his worry levels elevated slightly. But... Sam's face contorted into a slightly confused smile.

Dean stared at Sam's face for a solid second. "What? what? Sam? what is it?" He questioned.

"Dean... It's a cat..." Sam said with an amused chuckle. You (the cat) look up at Sam as he watches you.

"A Cat?!" Dean says. "How the hell did a damned cat get in?" He tries to maintain his focus on the road whilst being slightly pissed that there was a cat that could be getting hair all over his Baby.