I did not have my new Hankook Ventus V12 Evo tires on my car when I noticed my left rear was flat.

I took it back to America's Tire to have it checked and they found a broken GM ignition key embedded in the tire. The tip had broken off and what remained looked more like a small dull knife blade. It sliced right through the tire between the tread pattern....

They said they had never seen anything quite like it and are replacing it at no cost.....