An alien learning human kindness while also killing them. Some of the best moments of the film come from the unknown/scary atmosphere of scenes. Until it reaches an ending that only begins to make you question what the film is really about.
This film at least requires 2 or 3 viewings.
I don't think I've ever seen a film that has scared, amazed, and intrigued me this much after watching, since 2001: A Space Odyssey.