Do you believe in ghosts/spirits?

That’s really about it, a black mist. It was roughly the size of an adult torso, maybe a little bigger when it spread out. It didn’t make noise or do anything else that we noticed. It did have a presence you could feel that would catch your attention sometimes. One time our 8 yo nephew was over and was talking about something and mid sentence looked up and said something like “something black just went up the stairs”, then went right back to talking like nothing at all happened. Kind of made the hair on my neck go up.