The Twilight Zone

Jerry took a woodworking class in high school - I'm not sure what year, but let's just say it was at the latest 1988. He made a clock in that class; a mantel clock with a pendulum. This clock runs on a single size D battery. It is now 2009, at LEAST 20 years later. I am sitting in my basement being a little freaked out that I can still hear that clock ticking away in the storage room. It is ticking very, very loudly. Why am I freaked out? Because we have never, not once, replaced the battery in that clock. It has survived at least four moves over the years. I'm kind of scared to touch it or I'd tell you what brand it is!