Body Language
performed by Alexander Baker and Clair Marlo

The boys nickname the girl Eleven, or "El", after the tattoo on her arm. Scientists from the laboratory find a substance oozing from the walls of Joyce's home. At Mike's home, El recognizes Will in a photo. She uses psychokinesis to lock the door and prevent Dustin and Lucas from informing Mike's parents about her. Searching for Will, Hopper discovers a torn piece of El's hospital gown outside the laboratory grounds. Nancy goes with her friend Barb to a party at her boyfriend Steve's house. Will's brother, Jonathan, investigates his disappearance using his camera near where Will went missing. Hearing screaming, he runs and sees Steve, Nancy, and their friends in Steve's swimming pool, and he photographs them. Barb vanishes from the poolside. Joyce receives another call from Will, hears music from his room, and sees something coming through the wall.