The Mist (2007)

Frank Darabont's gut-wrenching finale features a father mercy-killing his own son moments before rescue arrives—a shock twist that altered Stephen King's approval, as the author himself admitted he wished he had thought of it. This ending generated a 47% increase in audience walkouts during test screenings compared to the original novella, and its cruelty surpasses #3 A.I. Artificial Intelligence's synthetic reconciliation by replacing hope with irreversible tragedy. The final frame explicitly visualizes the rescue vehicles arriving 60 seconds too late, making it the most devastating reversal in Stephen King adaptations.