A permanent marker, nay, the Permanent Marker. Its true name is technically Marks-A-Lot, and it is manufactured by Avery. This pen, however, has properties beyond its own construction. It has a felt tip and writes in pure black ink, not some dark blue knock off. It will write on anything and everything, metals, plastics, masking tape, ducks, hair, etc. When applied to the skin, the markings will last for atleast 4 days worth of showers and even when rubbing alcohol is applied, a shadow of ink remains as a reminder. Excellent for testing out possible tattoo designs or for jotting down not so short term notes to one's self. The only problem arising from this incredible durability is if you must erase the messages scrawled on your arm quickly (say, before a test with an apathetic teacher), quite a bit of saliva and elbow grease will be required. Most likely the same amount required to remove all the layers of one's skin. Prolonged writing on one's skin will probably cause an ink poisoning, but getting there would be a fun journey.