S1, E9: It's Day 14 of the Mars social experiment, and the 8 remaining celebronauts have discovered they are not alone on Mars. The hab's radar system has detected an unfamiliar signal inside the habitat; someone or something is co-existing with the crewmates and could threaten their survival if they don't act fast. If the celebronauts can't prove their home is safe, they will need to abandon the hab. This mission tests the contestants adaptability and will earn them another mission patch.