The Ninja Epidemic

You have a serious headache again. It's been bugging you a little all day, but now it's rediculous. You need to get some asprin. You go up stairs to the medicing cabinet and get out the asprin. As you close the mirror/door you notice a black shadow-like form fall from the ceiling to land between the tub and the wall. You turn around, but see nothing there.

Do you...