Twist endings are so common in movies nowadays that well-read film fans can usually see them coming a mile off.
But clever filmmakers are able to play off the knowing nature of modern audiences by toying with their expectations and folding that knowledge into the context of the narrative itself.
These 10 movies all featured a classic third act killer reveal, but thanks to sharp storytelling the result was pure slack-jawed shock among even the most knowing film buffs, because these reveals so brilliantly hid their murderous maniacs in plain sight.
Whether they made the actual killer such an obvious possibility that it no longer seemed obvious, cast an actor against-type in the part, or otherwise subverted what most viewers expected, these reveals were all brilliantly surprising.
And even if you somehow managed to genuinely guess the killer ahead of their big reveal, you should give yourself a firm pat on the back, because you were absolutely in the minority...