Lost in Space takes a sharp turn into high-concept psychological sci-fi with “One of Our Dogs is Missing.” The episode centers on the arrival of a mysterious, shape-shifting alien entity that mimics the form of a giant, menacing dog. It’s a standout entry for the first season because it effectively balances the series’ early “survival horror” atmosphere with the interpersonal dynamics of the Robinson family. The tension builds beautifully as the crew realizes the creature isn’t just a physical threat, but a psychological one that preys on their isolation and growing sense of vulnerability on an unknown world.

The episode is particularly memorable for how it utilizes Judy Robinson, giving her a more proactive and heroic role than usual. Her confrontation with the beast in the cave provides a genuine sense of peril that feels earned, rather than campy. While the special effects of the era are obvious, the episode succeeds through its moody cinematography and the underlying theme of trust. It’s a classic “monster of the week” setup, but it’s executed with enough suspense and character focus to make it one of the more atmospheric and enduring chapters of the Robinson family’s odyssey.