This is a Penseive. A Pensive shows all your thoughts and takes them out of your mind so you have a more clear view of what is going on in your mind. It is your thoughts that you put in a small pot. You take out your thoughts with your wand and do it just above your ear, and a silvery thing will come out of your head and then put it in the Penseive and it is a clear view of your thoughts.above