Mark Protosevich is an American screenwriter. He is best known for his screenplays for the films The Cell (2000), I Am Legend (2007), and Thor (2011). He has also written two remakes: Poseidon (2006), an update of The Poseidon Adventure (1972) for director Wolfgang Petersen, and Oldboy (2013), an adaptation of the 2003 South Korean film of the same name for Spike Lee.