At the start of 2017, I was experiencing odd things I couldn't explain. I would see what I was sure was a silhouetted figure in the corner of my eye, and turn to look but it would be gone. This happened several times a day whenever I was alone, no matter where I was, and it continues to happen nowadays. At this point I was unsure if I was imagining it, hallucinating or even suffering symptoms of a mental illness, but I know what I've seen and the frequency of the sightings confirms to me that this is real; I am either being followed by this entity, or it has attached itself to me.
One night around this time period, I had just got into bed and had been lying in the dark for only 5 minutes when I heard a metallic "ping" followed by a thud. I turned on the lamp to see what had happened and saw a small bullet casing in the center of the room on my carpet. I collect bullet casings and artillery shells, and I keep them on shelves against my wall, so the bullet was 3 feet away from where it had been displayed for years. The metallic sound I had heard was forceful, like the bullet had been thrown or hit across the room - there was no way it could have fallen.
That morning, I woke up and opened my blinds and was shocked to see a hand print with very elongated fingers in the center of the pane of glass. This could not have been the hand print of myself or anyone in my family, because first of all the fingers were abnormally long for any normal human hand, and the windows had been scrubbed and wiped clean the day before due to black mold. No one could have touched it during the night, and so with the bullet incident too, it cannot be a coincidence and leads me to believe that the black shadow figure I see (or equally another entity entirely) did these things.
They may not seem like experiences worth mentioning, but they were the 2 experiences that convinced me that what I was experiencing was not a figment of my imagination or a hallucination, but supernatural/paranormal activity. Since this I have experienced much worse, and I expect that my experiences will continue to get worse.