A long time ago (about 10 years ago) when I was 8, me and a friend of mine were in a field trip organized by school to visit one of our last kings' summer villas or something of the sort.
It was very hot, especially for spring. When we got there, it turned out that the estate was closed for visiting and the whole class got vexed, mostly out of the unbearable heat and boredom.
While we were walking back, me and that friend were at the far back of the line, where we always liked to be since we could walk at our own pace undisturbed. While on that field trip, we had a lot of spooky sightings but all of them where from our imaginations (that I'm sure 100 percent). However, what happened that day, on the way back was real, I have no doubt about it, since this time we both saw it simultaneously.
You know how you kick rocks when you have nothing particular to do, right? Well, while we were walking, I was talking to my pal, and he would kick a rock or two from time to time. Just then, he kicked a couple of jet-black pebbles about the size of ping pong balls right into a pile of horse shit (don't laugh). Just then, a pair of, as I remember them, angelic-like wings sprouted from the sides of the two stones. Both of them darted off to an opposite direction.
I saw the right stone fly off into the yard next to me, make an arc pattern over a couple of trees there and just dropped cold. When I asked my friend what happened to the other one, he said it just blasted up and fell into the yard across mine. Me and him had a falling out later on, but to this date I still remember all of this as if it was yesterday, still wondering whether or not I should find my old friend and have a look at the place ten years after the whole ordeal.
An alien probe, an act of God (I'm atheist), an insect, I don't know but what I do know is that it was like nothing I've ever seen before.