The Black Knight Ghost is a recurring enemy of Scooby Doo, with many criminals wearing the outfit to scare off people so that their criminal actions would not be discovered.
In the Spongebob series, Maleficent used her dark magic to collect all the Black Knight ghost suits, and enchant them all to make them all come to life. The Black Knight ghosts currently serve as Maleficent's elite soldiers and guards within the Forbidden Mountains since the Goons and Diablo are always traveling with her to other worlds.