Dread Baron is an evil Dick Dastardly lookalike who appears in Laff-a-Lympics. He and Mumbly led the Really Rottens team. Voiced by John Stephenson, Dread Baron was created because Hanna-Barbera staff weren't sure they could actually use Dick Dastardly and Muttley again. It later turned out they could have, but by that point the show was in full production.
In an authorized comic book published by Marvel Comics, it was explained that the Baron and Dastardly were in fact brothers. Like his brother, the Baron's schemes to cheat and win much more often than not blew up in his face. A true villain, he once was disgusted to learn his team had won an episode's events fair and square.
With the rights to Dick Dastardly's character resolved, the Baron's appearances since Laff-a-Lympics have been few and far between. In fact, very few of the Rottens were actual pre-existing HB villains, most being pastiches of the kinds of villains seen in classic cartoons. For example, the Great Fondoo was allegedly based on Abner K. Dabra, an evil magician in a 1963 Yogi Bear storybook.
In a dark parody on Robot Chicken, the Baron led the Rottens on a slaughter of members of the other teams, which led the survivors to plot brutal revenge through traps and ambushes. This was also a parody of the feature film Munich, which depicted the killing of Israeli athletes at the 1972 Munich Olympic Games and the vengeance that followed by Israeli commandos.