Rockin' Roller Coaster Terror is the 3rd level of the video game, Scooby-Doo! Unmasked.
Homing in on Maggie Xi's radio transmission, the gang goes to Rock n' Roller Coaster Land, owned by Daphne's favorite musician, the Guitar Ghoul. However, the park is being terrorized by a Guitar Ghoul imposter.
Stage 1: Clue Search
Scooby-Doo looks for clues in the 'Haunted Mansion' ride, where he encounters the Rocker Gals and finds a video of the Guitar Ghoul using secret passages to sneak around the park.
Stage 2: Searching for Shaggy
Scooby and Shaggy search for clues in the Water Park, but Shaggy slides down a waterslide. While searching for Shaggy, Scooby battles Strongman animatronics and finds a brochure for a band called 'Def Potato'. After finding Shaggy, they're both scared down a waterslide by the Guitar Ghoul and meet a girl.
Stage 3: Rescuing Daphne
Daphne is captued and held in the Circus Tent. In going to save her with a bat suit (not Batman related), Scooby battles Ghost Clown robots and finds Guitar Ghoul sheet music written by the girl he and Shaggy met.
Final Stage: Boss Battle
Scooby battles the Guitar Ghoul in the House of Mirror by knocking mechanical spiders into him. He's revealed to be Alvin Wiener, who recieved a mubber Guitar Ghoul disguise to avenge himself against the real Guitar Ghoul for Def Potato's (his band) failure. It's then revealed the girl is the real Guitar Ghoul who wanted to share her music, but not her life. In exchange for keeping her secret, she tells the gang some information.