Chalk of transformation

This piece of chalk looks normal, but when you write a single work on something, what you write about that thing that you wrote on becomes true. For example, you could write "unlock" on a lock, and it would unlock. You could write "invisible" on a chair, and it would turn invisible. It does not work on living creatures. So you could not, for example, write "dead" on someone's forehead and they would die - it does not work. Also, if the item you write on is magical, then there would be some contest of strength between the magic of this chalk and that of the item. As you write, the chalk becomes smaller as you use it up, and soon it will just "run out". You figure it has at least 6 uses, maybe a few more, but not more than 12 uses for sure. You can only write ONE WORD, not sentences or even short sentences. But it does "translate" your word into what you are trying to do - most of the time. So for example, if you wrote "crumble" on a wall, that would most likely be translated as "tear down this wall".