Halloween // Best way to hide face in a costume where your face is "in" the mouth?

Aside from just painting your entire face black, is there a better way to conceal your face for those kinds of costumes where the head of the animal/creature goes over your head so your entire face is in the mouth of the costume? I don't want to leave it as is because it looks dumb to me and takes away from the face I want you to be looking at...quick example