10. The Killer Was On The Floor The Entire Time - Saw
The Ending: The man orchestrating the deadly series of trials, Jigsaw (Tobin Bell), has been in the bathroom with Adam (Leigh Whannell) and Dr. Gordon (Cary Elwes) for the entire duration of the movie. The "corpse" lying in the middle of the floor suddenly stirs to life at the end of the movie, informing Adam that the key to his shackle was in the bathtub when he woke up, as a flashback shows us that Jigsaw is John Kramer, the terminally ill cancer patient shown earlier in the film. Kramer leaves the room, declaring his distaste for people's lack of appreciation about their lives, before sealing Adam inside as he screams for help.
How It Trolled Audiences: Even if, like many viewers, you were informed before viewing Saw that it had a marvelous twist ending, and one that could be guessed if you really paid attention, you almost certainly didn't guess it first time around (and if you say you did, you're lying). It was reasonable to expect Jigsaw's identity to be revealed at the end of the movie, though in honesty, most of us would have easier expected Adam or Gordon to actually be the killer. Instead, the bad guy has been hiding in plain sight for the entire movie, a fine work of deception that instantly made us want to watch the movie again and examine every frame. The troll turned out to be so successful that Whannell and director James Wan made a fortune out of it, with their franchise concluding on its seventh entry in 2010.