Alien Intruder [1993] DVD

A mysterious woman appears aboard a spacecraft and begins to seduce the crew one by one, forcing them to become murderously jealous of one another. The parallel 'plot' occurs within the dream pods, where on their vacation time the crew use induced dreams to take themselves to, for example, the wild west, or the 1950s. During these dream sequences the mysterious woman also appears, in pretty much the same role, despatching the crew members' fantasy female avatars and replacing them with herself.

The mysterious woman is of course the alien intruder, and her motive never becomes clear, as rather than speaking she just prefers to giggle irritatingly - and, of course, strip.

Left unsure what the point of the film was other than to set a cheap softcore in space (actually set as much in the 1950s and on the beach), it would probably appeal more to a softcore audience than a sci-fi one.