I only remember a scene of this (scary?) movie.
 

Edit #2: I found it XD It's the bye bye man.


I only remember the first scene (I think it was the first).

It's summer and the sun is shining in the 70s/80s and everything seems to be going normal except at one point the father of the family picks up a shotgun and I don't remember.. I think he had short brown hair and glasses.

Edit: I think the father shoots his own family to stop something (maybe from spreading?).

I think the scene may be an intro like 20-30 years before the events of the movie.

I know this isn't much to go on xd I've seen the movie I just can't remember.