Nightmare

Nightmare is a music group in "The Neon Phantom of the Roller Disco!," an episode of the Scooby-Doo and Scrappy-Doo animated TV series.

The group is likely made up of several young adults who aren't named and don't talk. They are really nothing more than undistinguished specks, although they look like they're drawn to resemble an orchestra, despite the fact they are a rock group.

History
They performed a concert at the Hollywood Bowl, attended by Mystery Incorporated, until it was put to a halt by the Neon Phantom.