Beetles had this awesome "feature" where they had "storage" under the back seat... next to the battery. There was this floppy fiberboard cover that went over everything. By the 3rd or 4th owner the floppy fiberboard cover was generally gone. Not only that, but the springs in the back, particularly if the car was owned by a college kid in a college town, had suffered a little. This meant that if the 4th or 5th owner slung his particularly-heavy book bag on the back seat, opposite the driver (as one would), the metal springs of the seat would occasionally touch down on the positive terminal of the battery and short to ground. Causing a piece of 4-gauge spring steel surrounded by sisal fiber and naugahyde to get very, very hot. But usually not until you'd gone to the ice cream parlor or Starbuck's or pool hall or whatever. There were three VW Beetle self-immolations in my college experience. No one I knew, but it was a common enough occurrence that we discussed it in my vehicle design class.