I teach on the top floor of a three-story school, where the higher the grade, the higher the floor. So I teach the oldest students in the school, but I see the younger ones in the hallway throughout the year.
Two or three times per year, usually when my students are coming in from recess, so they're hyped up, I come up with some BS excuse to walk my entire class down the hallway with the students I'll have the next year. I'll warn my students to be quiet in that hallway, since classes around going on, knowing that some of them won't be able to do it. I count on some of them talking in the hallway, because then I can get my very loud teacher voice out.
I get so loud that, not only does it scare my students into behaving, but it scares the other 150 students in the other 8 classes on that hallway. According to my coworkers who work on that floor, every year I do this, the students talk about me afterwards, like they're terrified of me. That's the point.
In reality, I'm really a nice teacher. I rarely yell. But it's better if the students don't know that before they become my students. It's better to put the fear into them early