I remember when I was 7 or 8 (because the GameCube had just come out) me and my Brother helped our cousin hook up his NES but he kept saying there was no point because he hadn't any games for it. We looked through a few buckets and drawers where is PS2 and PS1 games are and surely enough, we found an NES game. Eventually after giving this game a few tries I felt spooked, dunno why. Perhaps it was just the general tone of the point and click adventure.
Anyway, this game was Uninvited. Whenever I look it up or look up Scariest Video Games it's usually somewhere high on the list. Scariest NES game I ever played anyway.