Adams orders the crew to erect a force field fence around the starship to prevent further sabotage. It proves ineffective when the invisible intruder returns and murders Chief Engineer Quinn. Morbius warns Adams of his premonition of further deadly attacks, similar to what happened with the "Bellerophon". That night, the invisible creature returns and is outlined in the fence's force field. The ship's blaster weapons have no effect and the creature kills Farman and two other crewmen. Morbius, asleep in the Krell lab, is startled awake by screams from Altaira. At the same instant, the roaring creature vanishes.