Why did I freeze when I locked eyes with a random man? Help! Confused and scared

I was out for drinks with my sister last weekend and just happened to lock eyes with a man about halfway across bar from us. Something about him was so intense and...knowing, maybe? I'm not sure that's the right word. It just seemed like he knew what I was. I have never told anyone about being submissive besides a former boyfriend and a supposed Dom I meet on the Internet who turned out to not be that. But although I knew he couldn't really know, I just felt like he knew everything. He didn't look and I couldn't look away. I was stuck and my heart was racing and I was scared to death. I was scared he'd try to come over to our table. That he would tell my sister what I really am, who wouldn't approve. That he would demand my number or something worse. That I wouldn't be able to say no if he did. At the same time I almost hoped he would do one of those things, besides telling my sis. And I thought all those things in abt 2 seconds. Then I went blank. I don't know for how long, but I didn't hear anything anymore besides my heart, which I felt everyone could probably hear too. I just saw his eyes that felt like they were physically holding me in place. I felt completely under this man's control. Next thing you know I'm slipping off the front of those high ass bar chairs. Normally I'd be embarrassed but I was honestly too scared, confused, and, I realized later, aroused. My heart was sprinting and my hands sweaty. Then it penetrated that my sister was calling my name and asking me what the hell that was about. I didn't look at him again and got my things together, telling her I had to leave. Which annoyed her since we had just gotten their. But I took her keys and rushed out.

I just want to know if this has happened to someone before. Is this normal? Dangerous? Why did it happen?