After opening with the discovery of a wreck during the opening titles, the second scene of this sequel sees the police chief arrive late to an event where a school band is playing Petula Clark's hit, Downtown. The Chekov's gun moment in this film occurs when a deputy and sailor accidentally discover a power cable while searching for a missing person; that power cable later is used to electrocute the film's antagonist. Identify this 1978 film which has one of the most famous taglines in film history; a tagline often erroneously attributed to the original film.
Jaws 2