Tinder users at the SXSW festival on Saturday were encountering an attractive 25-year-old woman named Ava on the dating app. A friend of ours made a match with her, and soon they were having a conversation via text message. But when he opened up Ava's Instagram, it became clear something was amiss. There was one photo and one video, both promoting Ex Machina, a sci-fi film that just happened to be