This happened a few summers ago, and I am still very scared about seeing it.
My mom told my brother and I that it was our turn to take the trash out. Normally, I'm not very afraid of the dark, especially since my brother was going to be with me, but for some reason I had a very bad feeling.
To explain how far we have to walk away from the house to get to our trash can, I'll tell you the basic lay-out of my family's property. We have a two story house at the very front of our land, and a small backyard. Then there is a wooden fence with no door, and yet another backyard with a shed in the far-left corner, a garden in the left corner closest if you walked to the back, and the trash can is on the dirt beside the street, a little ways behind the shed.
So, my brother and I gathered up the trash and went out without turning the light on in the back, figuring it would be fine. We started walking back and I felt even worse. Apparently it was showing on my face in the dim moonlight because my brother asked me what was wrong. I didn't want to worry him, so I replied simply; "Nothing."
We got to the "Second backyard" and I wanted to turn and run. I'm not usually a flight person, I'm more of a fight person. But for some reason, my brain was screaming for me to run. My brother seemed completely oblivious and didn't seem to feel a thing. I was walking faster than him and got to the trash can first. And then I saw something weird.
There was this small black mass, with no eyes, standing on our trash can. The better way I can describe it was that it was about 3 feet tall, and almost comical, with the way it looked. Apparently, it wasn't looking at me, because it turned and grinned at me. And it wasn't a normal "Haha, hey, how's it going?" grin. It was an insane, malicious "I want to hurt you." grin. It dropped down from the trash can and stared at me for a few moments and then turned again, running across the street and disappearing into some bushes.
My brother came up and asked me what was wrong and I told him that we had forgotten the key to unlock the trash can. I put the bags that were in my hands down and bolted for my house, happy to get away from there. I felt really bad for leaving my brother behind and was really scared, and, just in case, I grabbed a long stick that I kept behind my door upstairs for protection and ran back out, unlocking the trash.
I have been scared of it since, and am very afraid to go out back to the trashcan now at night. It's been gone for a while, but my sister told me to not think about it.
I read online that it might have been a shadow spirit, but I've never heard of one that is that small though. I'm wondering if I was hallucinating and being weird, or if it was actually something.