relaxing spa getaway evolves into a prehistoric panic when Scooby-Doo and the gang uncover the horrible Phantosaur, an ancient legend come to life to protect hidden treasures buried in secret desert caves. But this scare-a-saurus doesn’t stand a chance with Shaggy around, after he finds his inner hero with the help of new-age hypnosis. Like, it makes him more brave and less hungry!

Overview from themoviedb.org