Fountain of Expies: Italian comic books of the late sixties were invaded by murder-prone Impossible Thieves with a K in the name (Satanik, Kriminal, and a few others). They were out of publication before the end of the seventies, with the exception of Paperinik and Cattivik.
Reclusive Artist: Up to Eleven with Zarcone (also known as "The German"), the mysterious artist who drew "The King of Terror" and disappeared right after delivering the penciled art. Between that and Zarcone being a pen name (as it used to be the norm in Italy back then), nobody has any idea where he disappeared to, not even the private detective the Giussani sisters hired to track him down. Also, the fans not even knew he existed for thirty years (most fan had read the first reprint, that had been redrawn by Luigi Marchesi, and those who had the original issue had only seen the name of the cover artist Brenno Fiumali and assumed he did the whole book), until the original creators revealed his name.