Ben (1972)

A lonely boy, Willard (Lee H. Montgomery), is good friends with Ben, a rat. Ben is also the telepathic leader of a pack of other trained killer rats which do his bidding. Also with Joseph Campanella, Arthur O'Connell, Rosemary Murphy, Meredith Baxter and Paul Carr. Sequel to Willard, also available here at Rare Movie Collector.