Christopher Markus and Stephen McFeely may have been responsible for bringing Marvel's Infinity Saga home, but their partnership with Marvel began with the more humble Captain America: The First Avenger. On the 10-year anniversary, the screenwriting duo shared some original ideas that didn't make it into the movie, like a giant Nazi robot Cap was supposed to fight.In an interview with Yahoo, Markus and McFeely, who would go on to write Thor: Dark World, Captain America: The Winter Soldier, Captain America: Civil War, and Avengers Infinity War and Endgame, shared their start with the MCU and original ideas for The First Avenger."A large chunk of the third act was Cap fighting this robot," Markus says.