When I was a freshman in college, I had what is to this day the most terrifying experience of my life. One night I had been up hanging out with friends until around 1:00am, when I decided it was finally time to get ready for bed. I lived in a freshman dorm, with LONG hallways of bedrooms and common/shared bathrooms in the middle of each floor.
I walked into our floor's bathroom and started getting ready for bed, brushing my teeth, washing my face, etc. While I was washing my face, I instantaneously had the wind knocked out of me and struggled to catch my breath. Nothing physically "hit" me, but I felt such a tremendously overwhelming feeling of evil behind me that I literally was paralyzed with fear. I couldn't move. For several seconds, I could not breathe.
I remember the pressure in the room changing and my ears literally popping. I knew that some "thing" was behind me in that room, and I swear to you, I "knew" that if I would have looked into the mirror to see what was behind me, I would probably be institutionalized (it was THAT scary!). I basically sprinted down the hall and into my room once I could move/breathe again, literally hiding under my covers and pillow until I FINALLY fell asleep quite some time later.
Approximatively 6-7 years later, I was talking with another man who graduated from that same college three years after I did. We had a lot in common, and had served as a Teacher's Assistant for the same professor. This man knew a bit about my family's history with ghosts and spirits, and asked me to share some of my stories. When I told him the story of my experience in that residence hall, he was stunned. He told me that the professor we both had worked for had told him years earlier that the campus had been struggling with a demonic presence at the same time I had my experience. He also said that our professor had an identical experience to my own in his office late one evening.
I have NEVER felt pure, POWERFUL evil like that before, nor have I ever felt as scared in my entire life. Part of me wonders what I would have seen had I looked up into the mirror, but I am mostly thankful that I did not.