Strange dynamic?

There is some dynamic in my group going on which I don’t understand. I’m mutual friends with this person and have nothing against her. But the people I meet around her are strange.

Let’s say I’m friends with A. A is a popular girl as I see she has a lof of friends. But there is a strange behavior from the people around her. Person B tells me something and talks behind As back. But cowers in As presence and would lie to please A.

People would do everything person A tells them to do and I can smell a little bit of peer pressure.

I don’t know why they’re scared nor do I know why they would do something else than they tell me in private. And other poeple who I can tell from their facial expression they think something else but do the opposite anyway. Or people eager to please her or me who is almost hanging out with her everyday.

I don’t know what this dynamic is. Why are people scared of her?

I’m grateful people treat me nicer but it kind of rubs me the wrong way and I don’t like the pressure. But she loves it.