Roy Scheider, Richard Dreyfuss, and Robert Shaw all gave iconic performances in Jaws (1975), but the movie's most memorable character might be the 25-foot-long killer shark. For most of the shark scenes, Steven Spielberg either filmed around the creature or used a famously temperamental animatronic fish who was nicknamed Bruce after the director's lawyer. For the cage-diving scene, however, Spielberg did something different. That sequence features the movie's only footage of an actual great white, and capturing it almost turned deadly.

Near the end of Jaws, Dreyfuss's Matt Hooper dons a wetsuit and enters a shark cage in an effort to lethally inject the shark that's been terrorizing Amity Island. To film long shots of the scene, divers and nature documentarians Valerie and Ron Taylor filmed a body double cage-diving with actual sharks. Valerie told Inside Hook that to make the 15- and 16-foot sharks in South Australia, where they were filming, seem bigger, they used a small boat, a scaled-down cage, and a "very short actor."

The actor wasn't an experienced diver, however, and he was nervous about being submerged in shark-infested waters. His fears turned out to be rather prescient. At one point, a 16-foot great white got caught in the boat winch connected to the cage and destroyed the rig while thrashing to escape. Fortunately, the actor wasn't in the cage when this happened. If he had been, the incident would have no doubt been fatal, according to Valerie Taylor.

The moment was a close call for the crew, but it made for some great footage. To viewers who didn't know better, the trapped shark appeared to be violently attacking the cage. Realizing what they had, the filmmakers changed the script to include the dramatic shot in the film. Originally, Hooper was meant to die in this scene. But because the real shark film was missing an actor, they had Hooper escape the cage at the last minute and survive.

A close encounter with a man-eater wasn't the only mishap on the set of Jaws. Here are more facts you should know about the original blockbuster.

[h/t Inside Hook]