4. Daniel Passes The Curse To Katie (Paranormal Activity 2)
One of the darkest and most interesting plot points in the series is when Kristi's husband Daniel realises that Kristi's demonic curse can only be passed onto a blood relative. Daniel then makes the grim if somewhat understandable decision to pass it onto Katie, seemingly saving his family in the process and kick-starting the events of the first movie, much to the distress of his daughter from a previous marriage, Ali. Of course, as we all know, this doesn't work out very well for Daniel and his family in the end...