The sound of a voice behind him caused Schatten to turn, and he found himself looking up at a very attractive dark-haired young woman. He didn't recognize her, but she seemed probably a little too old to be one of the students at Hogwarts, although she couldn't be too long out of it.
He couldn't speak in cat form, of course, and it would hardly be dignified to transform back on top of the counter. So he did the next best thing, spreading his front paws down in front of him and bending low over them, arching his rear end and tail up merrily and giving a friendly "MRRROW!" in reply.