When I was a kid we had a huge garden split into a neat lawned area at the bottom and a messy area at the top with long grass, tall hedges, and a few trees. Me, my sibling, and a friend were playing a few feet from the messy area, which was clearly visible.

I looked to the top of the garden and to my shock/horror there was a HUGE army helicopter flying really low. It was barely clearing the hedges and the trees, which were moving in the agitated air from the rotors. I saw soldiers gripping bars inside the helicopter, as the door was open. A few watched me as they flew past. The weirdest thing was that the helicopter was really quiet. Not silent, but given it was no more than ten feet above ground and no more than thirty feet away from me, it was way quieter than it should have been.

I was scared shitless and froze. I couldn't take my eyes off this helicopter until it had passed over the hedge into my neighbour's garden. As soon as it was no longer in sight, I swung about to freak out about it with my friend and sibling. Only they'd never stopped playing whatever game we'd been involved in. They claimed to have neither heard nor seen this massive army helicopter so close that I'd seen the eyes of the soldiers inside it.

I ran in to tell my mother and she thought I was making it up. My friend and sibling just laughed at me. Many years later I discovered the friend was a bit of a dick, and my family had been gaslighting me for years. Because of this I really don't know whether I was having a vivid hallucination completely out of the blue, or if I saw some kind of military stealth copter and the others thought it would be hilarious to pretend I didn't. Our house backed onto a lot of fields, and the wild area of our garden could easily have looked like an extension of it, so it's not totally implausible that the military were out practising something in a "secluded" area. I think there was even a military station nearby at the time. But I'll never be sure ...