Jaws is an NES game based on the film franchise of the same name, specifically Jaws: The Revenge, the fourth and final film in the series. However, it does take elements from the first.
In the game, the player pilots a boat across the sea, randomly encountering groups of hostile sea creatures. When the boat snags something in the overhead map, the perspective changes to a side-view. The player's boat releases a diver who battles various undersea threats such as jellyfish, rays, and smaller sharks. Occasionally, Jaws will appear on the map in the form of its familiar dorsal fin breaking the water's surface. If players collide with Jaws' dorsal fin, they can momentarily control their boat in the side-view encounter in an attempt to attack Jaws with depth charges. Jaws will always collide with the boat and release the diver into the water. Jaws will also appear after a brief moment if the player snags something in the overhead map with Jaws nearby.
Source: Wikipedia, "Jaws (video game)", available under the CC-BY-SA License.