When I was very young, my family lived in Cameroon for a while (Dad was an expat). Storms always scared me because we lived on the top floor of an apartment building and when the wind would pick up you could feel the building sway.

But there were 2 storms at night that got REALLY bad. The kind where there's barely 5 seconds between strikes. During both storms, the thunder would get louder and more frequent until it felt like it was right on top of us. Suddenly there would be a MASSIVE thunderclap, so big it made everything shake, and then... drums.

Deep and heavy, pounding to a consistent tempo, I could hear them so clearly. At the same time, the shadows around my room would begin to swirl and form into vaguely person-like shapes which began to move around my room to the rhythm of the drums. I would run screaming from my room to my parents who heard nothing of the sort, not even the massive thunderclap that started it. I'm not sure what they thought after the second time it happened, but we moved away shortly afterwards and I never experienced anything like it again.