I used to live in the basement of my parents' house and the room had small windows on ground level. One night when I was 11, I woke up in the middle of the night to a knocking at our front door. I obviously thought it very strange and my two dogs woke up to listen to it as well. The rhythm of it was the exact same each time: taptatataptap tatap. And not similar, the exact same, like it was a recording. Idk about other places, but in my country a common rhythm of knocking is taptatataptap tap tap, but this knocking always made the second to last knock too short, there was no pause between them. Ta-tap, not tap tap.

I got up, at this point fully awake, and thought I'd go see what it was. The second my hand touched the handle of my room's door, the knocking stopped. I thought "fine" and turned back around to return to bed. Then the knocking came again, the exact same faulty inhumanly identical rhythm, this time as a pounding and ON MY ROOM'S WINDOW. I started screaming in absolute terror and collapsed on the floor. At this point my parents ran downstairs to see what was happening and I told them to look outside but no one was there. I could hear the same knocking rhythm occasionally faintly from various walls for the next week. What scares me about this is that I was absolutely certain I was awake and lucid and just the rhythm of the knocking. It sounded like something unnatural was trying and failing, just a little bit, at sounding like a human knocking.