Hanna-Barbera Scooby-Doo...Mystery Comics #24

In "Mark of the Blue Scarab," Scooby-Doo stumbles into a hidden cave while chasing a mysterious shadow, uncovering an ancient artifact that sets the gang on a trail of ancient secrets and sudden transformations. With archaeologist Brad and the ever-skeptical Fred leading the charge, the team races to decode the Anthro-stone before a rival collector claims it—only to find Mandrell’s office locked and his bizarre transformation a terrifying reality. Written by Mark Evanier and illustrated with dynamic flair by Dan Spiegle, this 1974 mystery blends classic Scooby-Doo suspense with a supernatural twist, all wrapped in a cover by Spiegle that captures the eerie intrigue of the tale.