When I was much younger I had heard for the first time a swan circling the shore of my lake in the dead of night. It was this eerie swooshing sound, like huge wings, accompanied by the weirdest nasally grunting. This thing circled the entire lake multiple times, but I could see nothing in the dark.
Now, I was probably just high, as I usually was during that period, but I remember taking to social media to ask if anyone else had "heard something weird flying around the lake" the night before. Unfortunately, people thought I was talking about a UFO, and I wound up being ridiculed for it.
It took me years before I had finally witnessed a swan doing the same thing in the light of day, and was able to finally drop my half-baked fear that Nosferaru had been taking to the skies at night in my lake community.