Ellis (Out of the Blue, 1995, etc.) offers middle-schoolers more than a chill or two in her collection of short stories, featuring a variety of teenage narrators. In ""Tunnel,"" Ken, 16, learns that there are experiences even more uncomfortable than playing Barbies when he babysits a little girl and nearly loses her to a circle of vengeful sprites who live in an abandoned sewer pipe. The familiar classroom setting turns sinister in ""Knife,"" where urban survivor Curtis confronts the new kid, who is possessed by the spirit of a seal pup injured by Curtis years before. The Interact plays a role in the surprisingly unsettling ""Net,"" about Aidan, who is saved by a tantalizing bit of E-mail from riding in a car that is crashed on the road. A slip of temporal mechanics proves serendipitous for young Maia and her mother, a midwife, in the amusing ""Pinch."" Most memorable of all the offerings is ""Potato,"" where Selina recounts the horror of losing a brother to a religious cult, and the subsequent joy at their reunion. All the stories feature Ellis's taut and restrained prose, and most are as intriguing and finished as her longer works.