When you saw the car in the morning, did it have it's rear tires crossed waiting to go to the bathroom?? lol 
In all seriousness, I'd also say that it was either the AC or just condensation from the exhaust. Keep an eye out for it to verify where it's coming from.
In all seriousness, I'd also say that it was either the AC or just condensation from the exhaust. Keep an eye out for it to verify where it's coming from.