Adam the vampire

Adam became bored with his idle life and decided to do something for the world. He found a job as a university professor, in the literature department. He bought blood at night at the hospital, worked during the day and socialized with people, though he still preferred solitude. The new academic year began, and Adam sat in a huge auditorium, waiting for the first wave of students to arrive for his first lecture of the year.
When the bell rang, the young men and women took their seats, looking curiously at the new teacher.
Adam stood up and opened his mouth to introduce himself, but at that moment the door to the auditorium opened.