Complex sentence: Brak's voice was provided by Keye Luke in the original 1966 animated series; however in the premiere episode of Space Ghost Coast to Coast "(in the" Beavis & Butt-head parody) Brak and Sisto were voiced by C. Martin Croker.
Split into simpler sentences: Brak's voice was provided by Keye Luke in the original 1966 animated series. In the premiere episode of "Space Ghost Coast to Coast" (in the "Beavis & Butt-head" parody) Brak and Sisto were both voiced by C. Martin Croker.