This woman swallowed a felt-tip pen in 1986. Back then, she told the doctor and her husband what happened, but they didn't believe her. Now, 25 years later, she went to another doctor and they found the pen intact inside her stomach.
In fact, the pen was still working after they surgically extracted it, using a "combined endoscopic and ear, nose and throat procedure under general anaesthetic."
The doctors detected the pen following an MRI examination prompted by another stomach illness. The MRI clearly showed the writing utensil, perfectly preserved in her body. Apparently, plastic pens don't care about being submerged in acid for two decades and a half.
But how the hell did she swallowed the pen, you ask? According to her, she was poking her tonsils it near the stairs when she fell, swallowing it entirely. Why would you do this, I don't know. And how can you swallow a pen unless you are a sword swallower or Linda Lovelace, anyway? I would have died right there.