"One of the great pleasures of watching a movie for the first time is being surprised by it. There are few movies, however, that can claim to be truly surprising, to take the viewer on a journey they couldn't have anticipated when first arriving at the theater (or pressing play at home).
When it does happen, those surprises usually come from unexpected plot turns and twists, but an even rarer event is a genre shift halfway through, when the filmmakers rearrange our perceptions not only of the story, but of the very nature of the movie itself.
It's a difficult trick to pull off, which is why it doesn't happen very often. If a skilled director can pull it off, though, it makes for a unique and unforgettable experience, and this list has gathered some of the very best examples of that."