Spiders are a common phobia, and one that the cast of Arachnophobia (1990) was forced to confront during production of the 1990 movie. As the primary antagonists of Arachnophobia, these spiders weren’t computer-generated. Real spiders were constantly utilized in scenes in order to give the film a more realistic tone.

However, that realism came at a cost, as the film’s star, Jeff Daniels, later revealed. “Any shot that would deal with spiders was physically and mentally tough,” said Daniels during an interview with the Gannett News Service. Because spiders can’t be trained, many scenes had to be reshot over and over until the desired effect was achieved.

Because of how involved they were in the filming process, director Frank Marshall ensured that the actors he was working with would have no issues with spiders.

“Big Bob [an Amazonian tarantula used during filming] was sitting on the conference table in Frank’s office during my initial interview,” said Harley Jane Kozak, who played Molly Jennings.

Marshall also held a “spider orientation” so that the cast could get to know the spiders before they began shooting the film. “The kids ran over and picked up the spiders right away, so the adults were sort of shamed into it,” said Marshall.

In some cases, actors were forced to get a little closer to the spiders on set than they would have liked. Julian Sands, who played Dr. James Atherton, recalled shooting a scene where his character is covered in spiders while upside down.

“Frank thought it looked fake,” said Sands, “so he asked me to do it for real. I thought he was joking.”

Upon realizing that Marshall was serious, Sands agreed, albeit reluctantly. “I tried to think of it as an exotic facial massage,” said the actor.