Black Silhouette

When I was younger, I remember seeing constantly a black silhouette on doors and windows. It just took a peek and faded away, but fast enough that I never had time to actually try to talk or something. Besides I used to look at other side because it kind of scared me.

It was a simple thing and I'm actually having a hard time reaching 1500 characters, as I could have described this on a single paragraph.

I am here after reading some similar experiences here, and I thought I could get a answer, maybe.

That happened on many different houses and for many years. I never really did anything and I didn't told anyone. It was thin, never shown any hair and was taller than me at the time. Nobody on my family looked like that so I'm pretty sure it wasn't a person. It happened mostly at night, but I remember seeing it on sunlight too. It did not matter if there was more people on home and even if someone was close to where I saw it, they never said anything.

Thankfully, it haves been a long time since that last happened (specifically, after moving to what used to be my grandfather's house) but I just wanted to know if it was my imagination or something was really happening.

I would be very grateful with anyone that told me what that was. Sorry if this is trivial or obvious, but I don't think I have any psychical ability and I never got too much into this. If I make incorrect use of a word or something like that, that's because I have a limited English knowledge and I don't usually use it for something other than reading short text. I used word to spell-check and I hope I didn't miss anything on the process.

Thanks, and have a nice day.