I don't know where to ask this question, but it could be energy related.

When I was in college, I noticed something about one of my professors that was rather startling to me. It was as if he just 'wasn't there'. I'm not sure how else to describe it -- I could see him, talk to him, etc., but when walking by him or being in the same room with him, there was just no sense of him as a being. It wasn't that he was out of it or was ignoring his students...he was engaged and responsive. I would get more a sense of 'something' walking past a manequin in a store than I would walking past this guy.

It was really strange, and to this day, he is the only person that I've ever noticed this about. It's not something I would have noticed or thought about except that it was like an absence. And I noticed that absence.

Anyone else had an experience like this?

I wonder if he was just really, really good at shielding his energy and keeping it close to him.