The title did not come from the script, the director or the studio. In one scene, actor David Arquette improvised the phrase "Eight Legged Freaks" and that became the title. The original title was "Arac Attack" (in many European countries the film was released under that title).
When the town's people have fled into the mall, the mayor, Wade, asks the goofy sheriff's assistant Pete what the hell just attacked him. Pete answers: "A spider, man", swallowing the syllable 'a', making it an obvious reference to Spider-Man, Marvel's comic book superhero.
When the mayor sees all the people running towards the mall, he says the line: "If you build it, they will come!". It's inspired by the line : "If you build it, he will come." from Field of Dreams (1989) starring Kevin Costner.
During the car ride to the mall, Harlan is convinced the spiders are aliens. Chris responds "They are spiders are from Mars." David Bowie came out with 'The Rise and Fall of Ziggy Stardust and The Spiders from Mars' in 1972 and the spiders from Mars are referenced in the song 'Ziggy Stardust.'