Creepy Stalker?

I just had a really creepy guy in the office that did NOT want to leave. He just kinda kept staring at me. I had to come up with three different ways to say "I'm finished. Now YOU leave." before he would turn and walk away. And he turned back THREE times to look at me before turning the corner that is 10 feet from my door.

I've had stalkers at work before, but none as creepy as this guy. To summarize:

1. The friendly guy that I was kinda friends with who came into the office all the time to just talk.

2. The licquor store manager that came into the office twice a semester for 8 semesters to ask me out to lunch, and to ask why I hadn't called him for lunch. Even after he knew I was married.

I would like to avoid having another one. The other two were nice guys. Nothing creepy other than the constantly coming to talk and ask me out. This guy looked and acted creepy. I've informed a guy I work with that if this dude EVER comes back in the office, he is REQUIRED to come rescue me. At least I have a lot of nice men working in the office!