In my apartment I live with at least 2 ghosts. One is a victorian woman that lived in the structure that used to be on the property, the other is a drag queen. We made a deal, that the bedroom was off limits, and that they had run on the apartment when I went to sleep. They don't really cause any problems - and are pleasant to be around.
HOWEVER. At one point I was letting a friend crash on my couch, and she was dating a much older man. I had come home, and she was out. I could tell that something was off in the house, because the normal feel of the space was drastically off. It didn't feel like my place usually does. It wasn't inviting, and it was very confused, cold, and tense.
It was late in the evening, I was the only one in the whole building, and I was on my way out to the gym. When I stepped out of my bedroom I looked up and saw a man standing in my kitchen. Now, I could tell it was a man, but it was more like a dark opaque smudge in the shape of a man. The only clearly defined thing about him was his hair, it was a nutty dirty blond, parted on the left side, it was coarse and had a pronounced wave.
I pretended not to see him, because I was busy and didn't need to deal with that shit. I walked over right next to him, and pick up my gym bag. He slipped into the kitchen - the beaded curtain between the living room and kitchen barely even moved. I assumed he had left, and was just a transient ghost that just died somewhere around the area.
As I picked my bag up, he came out of the kitchen again, and I jumped a little bit... it was enough for him to know that I could see him. I grabbed my bag and he came at me, I held steady and pretended like it didn't happen. He went back into the kitchen, It was obvious he was looking for something frantically but couldn't find it.
I used this time to start walking to the front door. As I reached the front hallway I turned around and he was standing, in the center of the living room, looking right at me. I looked right at him, and he knew I could see him. at the point he moved quickly towards me, I ran for the front door. He was right next to me, I could tell he needed something, or was looking for something - but he was so confused and angry.
I hit the front door pretty hard, the man was standing right next to me. At no point had he touched me, or attempted to hurt me - but I was scared. I could feel how confused and frightened he was and it making me confused and scared. All I knew was that I needed to get out of there ASAP.
I ran out the front door and slammed it shut. He didn't follow me out.
I went to the gym, and did my thing. When I got home, the couch surfer was home and the apartment felt normal again. The couch surfer was crying - again I didn't feel like dealing with it. So I went to my room and slept.
In the morning we chatted. She said that the older man she was dating had a sudden heart attack and passed away earlier the day before. She showed me a photo of him and BAM - his hair was exactly the same as the smudge thing that had been in the place the night before. I told her what happened, and she started to dry again. We both concluded that after he passed away, he came over to see her - one last time.
I asked her to tell him to leave - she did, and I've never seen the smudge or had another issue in the apartment since.