The sheriff does not believe Carol and Mike about the giant spider, but their science teacher, Mr. Kingman, persuades him to return to the cave with large amounts of DDT. They find Jack's body, drained of fluids, and spray DDT throughout the cavern to flush out and then kill the spider. The apparently lifeless body of the spider is taken back to town to the high school gym, where Kingman wants to study it, concerned that whatever conditions created it may produce a whole race of giant spiders. A group of teenagers uses the gym to practice rock and roll numbers they are going to play for a school dance. The music awakens the spider and it crashes through the wall of the gym. The janitor, stopping to call the teacher, is killed.
