Yes, I've heard of mice in cars, chewing through hoses, etc. It's not uncommon. They're destructive little beasts. It's also possible to attract critters if you leave food or drink in your car!
I didn't have a mouse, I found a kitten. I was working, calling on my regular customers, and decided to stop in at a new salon. When I came back to my car, I heard frantic meowing. At first, I couldn't figure out where it was coming from, so I stood there for a few minutes, listening. It was coming from my left front wheel well. I figured it was cold and scared and looking for a warm place to hide. Well, I couldn't start the car and drive off, or I would've killed it. So, I called AAA for roadside service. He came and got the kitten out, and there I was in a parking lot off a major highway with this scared little creature. I walked back into the salon to see if it belonged to anyone who was there. Nope. Does anyone want a cute kitten? Nope.
I couldn't just leave it in the parking lot. I was almost done for the day, so I dumped everything out of my purse—it was a big purse—and put the kitten in there. I started the car and the poor little thing was so scared it peed in my purse.

I drove back to work to drop off my orders, told everyone what had happened, and asked if anyone wanted a really really cute kitten. Nope.
So WTF am I gonna do with this kitten? Unfortunately, I couldn't keep it. The apartment complex I was living in at the time had a "no pets" policy. It dawned on me that there was a pet shop in the mall down the street. I called and asked if they would take the kitten. At first, the guy said, you guessed it, no. I pleaded with him. "I know you're an animal lover, or you wouldn't be in the business you're in. I can't just turn it loose. It'll be dead in no time. Please, please, will you take it? Please?" I finally convinced him to take it, but I had to pay him twenty bucks to take it off my hands. Needless to say, I had to throw out the purse.