Ecto-X was a robot built by Egon Spengler to help the Ghostbusters bust ghosts. Unfortunately, Ecto-X worked too well and started to overshadow the Ghostbusters. Things went worse when a Computergeist possessed Ecto-X, captured the Ghostbusters, and went to the Firehouse to open the Containment Unit and free his imprisoned brothers and sisters. Fortunately, Slimer managed to save the Ghostbusters. The Ghostbusters were able to capture the demon because he surrendered. Since then, Ecto-X was remodeled into Ecto-Maid, and was now programmed to serve the Ghostbusters snacks.
- Ecto-X is similar to another robot named Robo-Buster. It should be noted that one panel has Egon erroneusly refer to Ecto-X as Robobuster.
- On page nine of Ghostbusters Issue #3, Ecto-X makes a non-canon cameo on a shelf rack in the Firehouse.
- He also is similar in appearance (and with the use of directives) to Robocop.