I, thankfully, didn't have far to go on my commute to get home when my tire stopped holding air, but I wasn't happy about losing a pricy tire at all. Then I started wondering what the heck this pointy thing in the tire was. It wasn't a nail, or much like anything I'd seen before.
After being mugged while commuting by bike just a few weeks before, my paranoia level is pretty high. I started wondering if this was some sort of projectile, perhaps from a nail-gun like device, and wondering if someone had shot it at me. No one I asked knew what it was, which further fed my fears.
I eventually posted on AskMetafilter, asking what it was. The helpful folks there had the answer. It wasn't a projectile, it was a center punch tool, but missing the handle. Somehow I'd managed to flip it up riding over it just exactly wrong so it would puncture my tire. I'm rather relieved I wasn't a target. I have a new Marathon installed already (Thanks Amazon overnight shipping) and got to enjoy installing it. Read about how much fun that is.
Of course, the all-knowing Facebook thinks, based on my research, that I now want to buy a center punch. They've started putting ads for them on my feed. Yikes.