My mom and I lived in a haunted apartment for 19 years, and we believe there was activity throughout the entire building, not just our apartment. We had a neighbor living directly upstairs from us, and for 3 years, he was the perfect neighbor. Then, one day, my mother told me he had started hissing at her when she left the building to go to a friends house. It was just the beginning of some extremely bizarre behavior out of him. He started banging pipes on the floor of his apartment, started threatening the landlady, and also a lot of other people in the neighborhood people as well. He especially liked to scare children and elderly women.
We knew something was terribly wrong with him, with his behavior changing so much. One day we were walking down the street, my mom said, hey, there he is. And she pointed at a man who looked just like the neighbor who was behaving badly. And then, out of nowhere, this man morphed into someone else, and then we saw another man, who happened to be the neighbor stepping out from behind a nearby tree.

If this was not weird enough, he came across the street towards us, and when he got right up to us, we could see his facing changing right in front of our eyes. Not just his facial expression, but the bone structure was actually changing right in front of our eyes, changing his facial features entirely, so that he looked like a different person. It was then that we understood that he had a possession going on. We knew we were in the presence of evil. The last we heard, he had been kicked out of a mental institution for behaving in a threatening way to the other patients.