Trivia: The film's cover of "Another Brick in the Wall" (Parts 1 and 2) were performed by a band called "Class of '99." The band was a super-group made up of members from prominent 80's and 90's rock bands. (Including members of Alice in Chains, Rage Against the Machine, and Jane's Addiction.) The band was formed exclusively to record the covers for the soundtrack, and disbanded immediately after the film's release.
Trivia: In the beginning of the movie, Marybeth asks a girl with a piercing where the office is. That girl is actually the director Robert Rodriguez's sister, and she has a tattoo in the same place where George Clooney had in From Dusk Till Dawn, another of Rodriguez's movies.
Trivia: "Buffy the Vampire Slayer" co-star Charisma Carpenter was approached for the role of head cheerleader Delilah. Carpenter turned down the role, feeling it was too similar to her "mean-girl" "Buffy" character Cordelia.
Trivia: The original script was written in 1990, but no studio was interested. When "Scream" became a hit, Miramax quickly bought the script and hired "Scream" writer Kevin Williamson to rewrite it to make it more hip and funny. Williamson was originally going to direct the film, but chose to instead direct the black comedy "Teaching Mrs. Tingle," since that film was based on an original script he wrote. Unfortunately, that film flopped while "The Faculty" was successful and became a cult favorite.
Answer: The aliens needed fresh water. All the infected were drinking bottled water. When the gang were examining the slug in the garage, it dried up and died from salt, like a snail.