Teacher's biggest dread

To be teaching a class of hyper-active teenagers who channels their energy to other things than studying. There were only 17 students in the class and yet, they are infamous. For the first time, I was actually worried.
I was allocated to THE class to relief a teacher who was hospitalized. Yes, the teacher was hospitalized. Who wouldn't be worried?!!??
When I told this to my husband, he said, "Long ago, it was the teachers that the students fear of, now, teachers are even scared to get into the class." He makes it sound as if I am being thrown into a dungeon. But quite close to how I was feeling at that time. I had been warned earlier by the head of Mathematics that this is a class to watch out for. So I really don't know what to expect.
When I came in the class, which by the way, the only class which has only one door unlike the other classes (to make it a little harder for them to run away from class in the middle of the lesson, i believe) , there was only 1 student. He was reading. 5 minutes later, a girl turn up. A while later, the school OM came to inspect. I think the head of Maths could have told him to back me up. Yes, I needed back up. Slowly the class make up to the supposed 17 students. As punishment for coming in late, they had to do detention. Too light a punishment for them maybe. Because they just looked bored.
SO after everything settled, I just continued to guide through an exercise I just gave out. They are not as bad as their reputation spells. They are just a group of students who have weak bladder, who has an attention span of a lightning bolt, whose mouth would start to itch if they do not irritate their classmates, the only ones who have an answer to rhetorical questions and the only ones who can ask the Head of Department to stop his nagging because he is exhausting their lesson time. I take my hats off for the last one. Something I have not seen a teacher done with their HOD. Expressing their thoughts :)