Why do so many movies use exactly the same scream?

Partly to save money, and then as an inside joke. The famous Wilhelm scream was recorded for a 1951 Western called Distant Drums, for a scene where a soldier wading through a swamp is grabbed and dragged underwater by an alligator. The recording was labelled, wonderfully, 'Man getting bit by an alligator, and he screams.' Creating sound effects was expensive back then, so Warner Bros. kept reusing the scream in its other films. It got its name from one of them: Private Wilhelm, a soldier in the 1953 Western The Charge at Feather River, who yells it when an arrow hits his thigh.

The scream might have faded away if not for Ben Burtt, a sound designer who stumbled on the old recording in a studio archive. He put it into Star Wars in 1977, as a stormtrooper falls after Luke Skywalker shoots him off a ledge. Burtt named it after Private Wilhelm and made it his personal signature, slipping it into every later Star Wars film made under George Lucas and all the Indiana Jones films.

Other sound designers caught on, and hiding the scream in a film became a tradition, a wink to anyone listening closely. According to the National Science and Media Museum, it has been heard in more than 400 films, usually when someone is shot, falls from a great height or is blown off their feet.

The voice is probably that of the actor Sheb Wooley, though nobody can be completely sure. Since 2023, the original recordings have been free for anyone to use.