Phallic parasites turn the residents of upscale Starliner Island, a self-contained community 12 1/2 minutes from downtown Montreal -- into sex maniacs: Who could have imagined in 1975 that David Cronenberg, the writer/director of this unpleasantly clever, queasy-making horror picture would become a critics' darling and genuine force to be reckoned with in mainstream filmmaking circles? A young woman (Cathy Graham) is found brutally murdered in her sterile Starliner Towers apartment; her killer, Dr. Emil Hobbes (Fred Doederlein), has cut his own throat. Hobbes, it turns out, was attempting to genetically engineer a parasite that could live within the human body and assume the function of failing organs. Instead, he created a venereal nightmare, a crawling, penislike slug that enters its hosts through the nearest available orifice and drives them into a sexual frenzy. It's up to Dr. Roger St. Luc (Paul Hampton), who runs the Starliner Towers clinic, to try to stop the orgy of the blood parasites. The plot's porno-movie echoes are underscored by the flat lighting, expedient performances and staging -- there's a lot of walking in and out of frame -- and dicey sound quality, but Cronenberg clearly has more on his mind that sexploitative titillation. Cronenberg's brand of body horror isn't to everyone's taste, but to call him a reactionary anti-sensualist who metes out grotesque punishment for sins of the flesh -- as detractors have -- is to miss the point. His beat is the underbelly of the mind-body schism, and illness as metaphor is his stock in trade. It's no great leap to make the argument that a libido-liberating sex parasite is just what the residents of Starliner Towers need to shake them out of their prefab anomie. And Cronenberg has a sense of humor: Who could not laugh at the scene in which two giggly pre-adolescents spot a slimy parasite crawling through a mail slot and run screaming, "Ewww -- gross"?