Tetsuo: The Iron Man (1989)

Mad with pain by the festering wound in his thigh, an extreme sado-sexual "Metal Fetishist" dashes out into the street, and is accidentally hit by the car of a white-collar worker and his girlfriend. But, strangely, instead of dying, the salaryman finds himself before a mysterious and agonisingly majestic transformation--one that twists and bends the pliable human flesh, inextricably intertwining it with the strong and cold iron. Now, there is no turning back, and nothing can stand in the way of the glorious final mutation. Is this the beginning of a new era?