Night Owls, what is the creepiest thing that happened to you when everyone else was sleeping?

A few years ago, I was working late on a project in my workshop around 3 in the morning. Everything was dead quiet, you know, that kind of silence where you can hear your own heartbeat. Suddenly, I heard the distinct sound of someone tapping on the metal roll-up door from the outside. I froze, thinking maybe it was a drunk or someone looking for trouble, but when I peered through the small security gap, there was absolutely nobody on the street. It was just an empty, dark road.

The creepiest part wasn't just the tapping, but the rhythm of it. It sounded like someone was counting, like a slow, deliberate knock. I grabbed a heavy wrench just in case and stepped out, but the air felt weirdly heavy, almost like the temperature had dropped ten degrees in a second. I stayed out there for a good ten minutes, but not a single car passed by and the streetlights were flickering like crazy. I ended up packing my tools and leaving early, and I honestly didn't go back to the shop late at night for a long time after that.