nazi teacher
A teacher that is never satisfied with the work of their students, always finds something wrong with them/their work even if there is nothing wrong at all, and punishes them because they looked wrong at the teacher.
Teacher: Mr. Smith, you misspelled a word in your 200-pages paper, that's an F.
Student: You're such a Nazi teacher. You'll pay for this.
Student: You're such a Nazi teacher. You'll pay for this.