I accidentally tattoed myself with a technical drafting pen some 20 years ago. If I recall, I had had a drink or two, an inebriated fraternity brother unexpectly came into my room looking for food or something, and I stuck myself in the hand. I have a small black dot there. I'd classify it as "prison" style. It was tempting to turn it into a teardrop, but I eventually chose to leave it as is. Since, it's gradually faded and begun blending in. I know that any more serious work would eventually do the same, so I've chosen not to perform any additional inkwork. I do, however, continue my venture into accidental body modification. I have a few scars courtesy of the woodshop and have experimented with accidental branding with the soldering iron.