Hounded (2001)

Jay Martin is a 13-year-old who is competing for a scholarship with the headmaster's son Ronny. The headmaster, Mr. Vandusen, steals Jay's presentation and gives it to Ronny. Jay breaks into Ronny's pool house while the Vandusens are gone. Their show dog Camille discovers Jay and follows him home. Camille goes crazy and wrecks the Martins' house when she goes too long without her medication.