so I'm making this game called Rick-Roll 6: The Dark Lands, and I wanna add a haunted castle level and add ghosts *and when I thought about doing that, I thought of the Boos from Super Mario Bros.* but, there's an issue, I don't know how to program one to act like a boo. I don't know how to make it stop when your looking at one, and I don't know how to make one chase after the player when they're not looking. So if anyone could give me some tips on how to make one, I'd greatly appreciate it.