Lillian is at a live concert watching her favorite band perf…

Lillian is at a live concert watching her favorite band perform. While she was focused on watching the lead singer jump around the stage, a fan ran up on stage in a bright green praying mantis costume. Security quickly reacted and swiftly got the fan off stage. Weirdly enough Lillian does not recall seeing the fan run on stage. She only realized that the situation had occurred when she was reading a news article about the concert the next day. What phenomenon was Lillian likely experiencing?