about a high school that offered kids a field trip to some place where they have a cave systems and some kids go and when they arrive to their hotel an employee tells them an urban legend about a giant worm that lives in the caves. The next day when they go to the caves, while in there the ceiling collapses and the kids get stuck in there and try to find a way out. They end up getting scared and stuff and one of the students goes missing and is later found, but she was scared and said she saw the worm. They find their way out but they go through some other stuff. Can't remember though. Please tell me the title of the book if you know it or sounds familiar.