The Vanishing
This main character of The Vanishing just wants to understand his ex-girlfriend, which he eventually does in a way. The person who killed her ends up burying him alive as well! This is a good way to show him exactly what she went through until the very final breath, but it was a bit too extreme.
The Wicker Man
There is a certain kind of human fear in this movie that is hard to match. In The Wicker Man, we follow a pompous cop who is investigating a cult. As the movie goes on, he realizes that there was no missing girl. In reality, the islanders lured him in there so that he can be the sacrifice to the gods!