I have seen these my whole life.  I didn’t know what they were called until now.  I’m 59 and I’m not crazy. I see them at night and day.  I’m not sure what everyone else is seeing but mine are always related to death.  People I care about or people I know.  At first they frightened me but over time I learned that’s why they are there.  I’m not trying to scare anyone because maybe yours are there for other reasons.  This is just my experience.  They don’t scare me but I do feel unsettled and the sense of doom only because I know why I’m seeing them.  There not there to hurt me just warn me.