Possible Clues:

• Movie with a mechanical shark
• Best Picture nominee with three sequels
• 1975 summer blockbuster
• Shark tale of 1975
• Movie with an iconic theme that starts with two alternating notes
• Film with a distinctive alternating two-note sequence in its score
• Crocodiles' powerful features
• Movie with a fearsome fish
• Top grosser before ''Star Wars''
• Movie with famous 'dun dun' theme music