 In the original ending Jake is eaten, and the shark is bloodily impaled by  the front of the ship. In the alternate ending the shark is speared on the  end of the boat as usual but blows up instantly. A long shot from the  original Jaws movie shows the headless shark drifting towards the bottom. Cut  back to the surface where the three survivors are clinging to bits of the  broken ship and Jake is floating around, bleeding.  This version also misses  out a 30 second section of shots showing the shark perspective from behind  the boat as it follows then dives, before reappearing in front of the boat.