Dirtification

When I was young, I noticed I have a light brownish mark on my skin right over my ribs. I didn't know what it was, so I asked my mother. My mother said, "I guess it is dirtification setting in." I thought that was the coolest disease I had ever heard of. Whenever I was with my friends, I would show them this mark and tell them proudly that I had a disease known as "dirtification". I'm not sure how old I was when I realized it was just a birthmark.