a full moon, or a new moon?

Today in class, the professor kept making comments that she wasn't feeling too well. At one point, she just up and left the classroom quickly with a bag. Everyone was a bit confused. Moments later, she walked in where a werewolf mask (the kind that goes completely over your head). None of us could stop laughing! She went on with her lecture for a minute or two until she couldn't take it anymore. She has got to be on the coolest professors I know.