I have seen shadow people many times, mostly while waking up from sleep paralysis with the feeling of someone is in the room.
I don't want to make up stories or memories but many times I felt that this thing that was in the room was not human and evil. It usually looked so dark, without any defining feature just a darkness (which was more dark than night darkness).
Every time I would awake from a nightmare or a sleep paralysis, I would see that darkness in front of me. But once I get fully awake it would disappear so I just forgot about it until I came in front of a site about shadow people.
When I read the stories I became dazed for days. It wasn't until later that I saw one very clearly. I was reading a book late at night when I noticed something from the corner of my eye. In those days and I still sleep in the ground or in the floor, I just don't like sleeping in beds. When I turned around to see what it is, I remember very clearly seeing a grey ball of smoke or what can be described as a grey orb as the size of football, more smaller than a football. It was transparent, almost invisible. When I looked at it, it quickly ran away and hid in the darkness behind a cartoon box where I used to put my books in. It looked like it was floating and running in the same time because it was so close to the ground and it didn't make a sound, it was so clear. I thought it got startled because I saw it.
I still feel them from time to time but I never seen them as clearly as that one. The last time was about six months ago when I had a sleep paralysis. When I opened my eyes while still in SP I saw like shadow moving very fast. I left the TV on that night because I felt they were around but just before I completely woke up I heard very clearly a growling coming from one of the side of the room. The closest sound I found was the growling of hippos. They were two consecutive ones but at much faster pace than hippos.
I couldn't come back to sleep so I kept listening to the Qur'an the whole night before I came back to sleep.