Supposedly, M. Night Shyamalan crafted this fatuous and arbitrary riff on mermaid legendry as a bedtime story for his children. If so, he's utterly failed at adapting it to the somewhat higher standards of less partisan audiences, like nonimpaired adults and the neighbor kids. Think very carefully: Do you want to spend the better part of an evening cooped up in a dingy Philly apartment complex, listening to a colorful (read: ethnically insensitive) cast of losers discuss the fate of a fish-girl out of water ' especially when said discourse entails reciting ludicrous fairy-tale names in voices better suited to MAD TV's Mrs. Swan? Get ready to learn about 'narfs,â?� 'scrunts,â?� 'tartuticsâ?� and other creatures obviously created on the fly, and then to apologize to the makes of The Da Vinci Code, who can point to this misbegotten mess as proof of what a movie that's all exposition really sounds like. Never has the evidence been so clear that a once-promising director has gone completely insane, yet seldom has said proof been so all-fired dull. Throw it back.