1.Put spider eggs in her bag.

This tecnick is simpler than it looks cause she wont know it is you if you are a good spy. When all of the students are down staires with the teacher you go in her office and delicatly deposit the spider eggs in her bag and while she will be explaining in class, the eggs will hatch and all the baby spider will run out of the bag. You will lose at least 40 minutes of the class!