No, that would not be bestiality because bestiality is sex between a human and a lower animal(m-w.com). As long as the alien has human-like parts and is a humanoid it would not be a "lower animal" Have you ever seen Species? I guess if its an entity that can "shape shift" and stuff then we would have to invent a whole new term since that isn't really an animal or human or whatever. I'd do that hot half-Borg chick from Voyager tho for sure.:thumbsup: