Fede Alvarez: We didn’t do any CGI in the movie. There’s no CGI in the movie. Everything you will see is real, which was really demanding. This was a very long shoot, 70 days of shooting at night. There’s a reason people use CGI it’s cheaper and faster, I hate that. We researched a lot of magic tricks and illusion tricks. [Like] how you would make someone’s arm disappear.