Arcane Grafitti

This spell allows you to inscribe your personal rune or a short message, which can be no larger than 2 feet tall and consist of no more than six words, on a nonliving creature or object. The writing can be visible or invisible. An arcane graffiti spell enables you to etch the words upon any substance (even stone or metal) without harming the material upon which the mark is placed. If invisible graffiti is made, the casting of any spell within 30 feet causes the words to become visible for 5 rounds.