The Tetsuo series of films.
A "metal fetishist", driven mad by the maggots wriggling in the wound he's made to embed metal into his flesh, runs out into the night and is accidentally run down by a Japanese businessman and his girlfriend. The pair dispose of the corpse in hopes of quietly moving on with their lives. However, the businessman soon finds that he is now plagued by a vicious curse that transforms his flesh into iron.
A Japanese salaryman finds his body transforming into a weapon through sheer rage after his son is kidnapped by a gang of violent thugs.
When the son of an American man and a Japanese women is killed, the man transforms into Tetsuo.
