S2E8 · Chapter Eight: The Mind Flayer

Complete story — includes the ending

The pack of Demodogs attack the lab, killing all of the scientists minus Owens. Will is sedated, after Mike deduces he is a spy, so that Will doesn't know where they are. Mike, Joyce, Hopper, Bob, Owens, and an unconscious Will escape and take refuge in a room when the power goes out. Bob leaves and manages to restore the power and open the doors. Mike, Hopper, Joyce, and Will escape, with Owens staying to guide Bob. After hiding from a Demodog, a broomstick falls to the floor, triggering a chase; Bob is killed by another Demodog. The group is rescued by Jonathan, Nancy, Steve, and the other children. At the Byers house, they name the monster the "Mind Flayer", who wants to conquer their world and kill them all. They manage to get Will to contact them in Morse code by telling him good memories of his childhood, with Will telling them to close the gate. The Mind Flayer detects where Will is and sends a Demodog. Eleven arrives, kills the Demodog with her powers, and reunites with Mike and the rest of the group.