The last 20 minutes or so. Special mention goes to the scene where Josef enters Aaron's home, films him while he sleeps, and then silently cuts a lock of hair from him.
The ending. Josef axes Aaron in the head in broad daylight, after Aaron was fairly convinced that meeting up in the day would be reasonably safe.
And then Josef gives us one last Jump Scare by getting his face in Aaron's camera (which filmed the whole thing) and screaming. He knew it was there the whole time.
