A rip-off of Jaws from Roger Corman’s New World Pictures, with all the New World virtues intact: it’s a fast, well-made, entertaining film with enough cheap thrills for the action trade and plenty of in-jokes for the cognoscenti. Bradford Dillman accidentally releases a tank full of mutant piranhas into a mountain stream, and as they swim downriver, they attack Keenan Wynn, a summer camp counseled by Paul Bartel (director of Eating Raoul and Death Race 2000), and a beach resort managed by New World stalwart Dick Miller. Director Joe Dante betrays hardly a trace of human values, but his cutting is the most evocatively Eisensteinian to be seen since Russ Meyer’s Vixen.