Arachnophobia's creepiest star was an Amazonian tarantula named Big Bob
"They stare right at you," said the film's star, Jeff Daniels.

Horror movies are an excellent way to face your fears. Our own personal anxieties can sometimes feel inescapable. But when you are allowed to see those fears in a film, it provides you with a unique opportunity to confront what scares you, knowing that it can’t hurt.
While Jeff Daniels didn’t necessarily have a fear of spiders when he starred in Arachnophobia (1990), he certainly had a healthy wariness of a certain eight-legged co-star.
“I didn’t really mind the little spiders,” said Daniels during an interview with the Southam News, “but when they brought out the big guy...”
The “big guy” Daniels was referring to was Big Bob, an Amazonian tarantula far bigger than your run-of-the-mill household spider.
“You spread him out and he’s nine inches across,” said Daniels. “He’ll rear up and hiss. If I got closer than five feet to him, I’d start getting worried. These big guys are terrifying to look at. They stare right at you. It’s a very strange feeling. You sense Big Bob had a personality - and a plan for you.”
Despite Daniels’ nervousness regarding Big Bob, he certainly had more than a few opportunities to become familiar with him. Plenty of Daniels’ scenes required one-on-one between himself and Big Bob.
“It took us two weeks to shoot a sequence that lasted only seven minutes,” said Daniels. “And every morning there was only one actor on the call sheet - me. All the other actors had wrapped. I was all alone - except for Big Bob, of course.”