File this under the oddest story you'll hear all day:  A black felt tip pen that was recently recovered after spending 25 years in a woman's stomach - and it still works!

The case, which appeared in the British Medical Journal Case Reports, described a 76- year-old British woman sent to a GI specialist because of weight loss and diarrhea.

She was diagnosed with severe diverticulosis, a condition that's common in older people in which small pouches bulge out from the colon. But when doctors did a scanning test of her belly they noticed something strange: "A linear foreign body in the stomach."

That foreign object turned out to be a pen that the woman swallowed 25 years earlier.

According to her gastroenterologist Dr. Oliver Waters, who authored the case report, she was standing on her stairs using an uncapped pen to poke a spot on her tonsils. She was also holding a hand mirror to guide the pen to the exact spot. Somehow, while doing this, she lost her balance and stumbled. The fall managed to push the pen down her throat. It glided down her gullet and found a home in her tummy.

She told her husband and her doctor what had happened, but they were skeptical of the story. X-rays done at the time were normal and found no trace of the pen. Flash forward to the present, to a different doctor and even better stomach-scanning technology to investigate the case of the missing marker. More than two decades later a scan hit pay dirt: The pen.

But most important to this story - the verdict:  did the pen still work?

After bathing in stomach acid for a two-and-a-half decades, the pen was corroded and the plastic was flaky, but, amazingly, the pen still had usable ink and could write!

The Body Odd - Swallowed pen still works 25 years later.