Ruby is 14, with a star-shaped gem on her belly. She listens to hip-hop, carries a yellow cell phone and loves sushi. In her online journal, she puts this on her to-do list: "Practice looking flirty in the mirror." We're talking, of course, about a troll. This fall, the short, ugly dolls that collectors have been after since the 1960s are about to be reborn. DIC Entertainment is bringing them back as skinny, purse-carrying, teenage girls with crushes on boy trolls (they wear jeans and sneakers and don't look like the old trolls, either). Andy Heyward, CEO of DIC, says the new line of Trollz will be arriving "like the Normandy invasion." In addition to their doll incarnation, the characters will appear in direct-to-video movies, videogames and books and as part of a fast-food promotion. Online, 'tween fans can create their own trolls and mix potions that cause (and cure) zits. The Trollz are different from other vintage brands--like the Care Bears and Strawberry Shortcake--in that a new story line has been invented to match their back-to-school wardrobes. The Cliffs Notes version: five girls named after gems (the others are Topaz, Amethyst, Onyx and Sapphire) live in the town of Trollzopolis and must stop the evil gremlin Simon--a "rebel without a cause or a sense of style"--from taking over. How do you know he's the villain? Duh. He's short and ugly.