Pen

I swallowed a pen. A black marker, to be precise. It was in a moment of discombobulation, when I couldn't quite work out a difficult mathematical problem involving a knight on horseback, relativistic speeds and a single car garage. You see, I have this terrible habit of chewing on my writing instruments in times of stress. Sometimes the consequences are most terrible. Have you ever had your mouth filled with black, oily ink? It has the slight taste of iron and is awful to get out.

On this particular occasion, my mouth was stained black for days and I was forced to lock myself in for the duration. I brushed my teeth till the gums bled rivers of ink stained blood and emptied five bottles of mouth wash. I felt like an obsessive compulsive, always scrubbing, never clean.
In the end I visited my doctor. She was forced to inform me that the staining would be permanent and that there was nothing I could do about it. I wear scarves now to cover my mouth.