The Blue Scarab is the titular villain from "The Scarab Lives!," the first episode of Scooby-Doo & Scrappy-Doo.
He was voiced by Pat Fraley.
The Blue Scarab is a comic book superhero created by Jerry Sloan; however, his assistant, Howard Gruger, wanted to create his own designs and grew tired of being an "unknown assistant." Howard had knowledge of an unreleased future Blue Scarab issue, where the Blue Scarab turned heel and became a criminal, and decided to use the story as a blueprint for his own plans. He dressed up as an evil version of the Blue Scarab and appeared to Sloan, threatening him to cease drawing Scarab comics.
The evil Scarab's appearance drew the attention of Mystery Inc., especially Scarab superfans Shaggy, Scooby, and Scrappy. The gang encountered the Scarab, who stated that he would turn to crime unless Sloan gave in to his demands, and afterwards, the Scarab went on his crime wave; robbing a jewelry store and a bank before targeting a museum. Scrappy's first attempt to capture the Scarab saw him tackle Howard, who scoffed at the stories of the Scarab actually appearing.
As it turned out, Scrappy was (accidentally) accurate, as Howard was revealed to be the villainous Scarab due to his art skills, his knowledge of the issue centering on the Scarab's heel turn, as well as the fact that he was the only one in the hall when the villain disappeared. Howard revealed his bitterness over being Sloan's assistant, as well as his plans to create his own characters, right before he was arrested.