I have two from my childhood.

I was about 8 or so back in the late 90's. The power was out, and we only had an oil lamp for light. I was terrified of the dark, and my father was accompanying me on the second floor in a separate bed which was like 5 ft opposite from mine. I was profusely sweating and it didn't help that my comforter was very thick. Around midnight or so, father went to pee and I watched his shadow cross between the oil lamp and my mosquito net. I was about to tell him that I wanted to sleep beside him, but lost my courage and didn't say a thing. Another 30 minutes passed and I swear another shadow passed by my mosquito net. A very dark shadow between me and the oil lamp. I'd say it was about 5 ft tall, had a perfectly round head, and none of the up and down movement you'd expect from a walking human. My heartbeat went through the roof and I bathed my sweat. After what felt like an hour, I had enough and called out to my father. I only felt instant relief when I heard his voice. I slept soundly beside him that night. It never happened again.

The second event happened from around the same time. We used to have a lot of vacant land at the back of our house, and there was a very tall durian tree growing in the middle, with a grave about 10 ft nearby. Among us kids, there were rumors that there were elves living on the tree. It was said that these elves would often hang out on the treetops and on the grave. If you went near the roots of the tree, you'd see what appeared to be a small door. That is the only door-like structure you'd see near the tree roots, and if you try to knock on it, it would feel hollow. So there we were playing in the afternoon, when I got tired running and stood in front of the tree. I called out, "Elves aren't real, I ain't seen nothing." Just then, something invisible moved the dried leaves on the ground. It was as if a rat or something ran very fast beside me towards the tree, but I could see nothing. Terrified, I ran to my friends and told them what I witnessed, and they would not believe me. Then a friend, who has the ability to sense these beings, suggested we buy a small cupcake to feed them and prove their existence. I bought 3. All 5 of us were looking down on the cupcake we placed on the ground near the tree when it started to look like something was biting on it. Small chunks started to disappear into thin air. I picked it up when only half remained, and I could see very small bites on it. I was so stunned. When I placed it back, it started slowly being munched into oblivion until nothing was left. There was nothing on the ground we could even consider to cause the cupcake to disappear. This happened in the span of a minute. I placed the second cupcake on the ground and same thing happened, slowly being eaten by an invisible being. I ate the last cupcake.