Scooby at the Center of the World/Scooby's Trip to Oz/Dog Tag Scooby

Plot:

In Carlsbad Caverns, Rock Monsters and giant bats terrorize Scooby. / Scooby dreams he's a character from "The Wizard of Oz." / Shaggy, Scooby, and Scrappy inadvertently enroll in a rigorous army training course.