OK, here's what happened to us:
One summer, my mother enrolled us all in swimming classes. Every day for a couple of weeks, we drove to the outdoor pool. No one ever locked their car doors then. One day after everyone's lessons were over, we went out to the car and when my mom turned it on, EVERYTHING in the car was going - the fan was on full blast, the radio blasting, windshield wipers, lights, everything.
We assumed someone had gone into the car, and turned everything on as a joke. Hahaha. Very funny.
Next day, same thing happened. Now, Mom is pissed off, cus someone is obviously going into the car when we're not looking.
The third day, she locked the doors. After our lessons, she unlocked the car and turned it on - SAME THING.
The fourth day, she locked the doors AND whoever wasn't at their lesson had to sit and watch the car. And we did, cus we wanted to catch the bastard who was doing it.
That afternoon, when she unlocked the car, not only was everything on, but there was also the god-awful smell I was talking about before. I swear it was the smell of death, I've never smelled anything like it before or since. We had to drive with all the windows down, it smelled so bad.
When we got home, my mom tore the car apart and jammed up under the driver's seat was a small black book with a pentagram on it. I remember it looked old. She started yelling at us all "Who put this in the car?" None of us kids had seen it before. She tried to burn it, and it wouldn't burn. She left it outisde in the back alley in the garbage bin until my dad got home and then I don't know whaat my dad did with it.