One easter egg in Scoob! shows that the Hanna-Barbera villain Dick Dastardly (Jason Isaacs) finally stopped the coveted Yankee Doodle Pigeon at some point before the events of the movie. Scoob! takes the Mystery Inc. gang on an adventure of worldwide proportions when Shaggy (Will Forte) and Scooby (Frank Welker) split apart from the group and get recruited by the Blue Falcon (Mark Wahlberg), Dee Dee Skyes (Kiersey Clemons), and Dynomutt (Ken Jeong). The new heroic team sails in search of the three dog skulls of Cerberus that Dastardly is gathering to retrieve his dog, Muttley (Billy West), from the underworld.
Dick Dastardly and his canine friend Muttley are two of the most famous characters from the Hanna-Barbera cartoons. Their origin traces back to the TV show Wacky Races, which premiered in September 1968, one full year before the debut of the original Scooby-Doo series. In the show, 11 racers had to compete against each other to win the title of "World's Wackiest Racer" and Dastardly always ended up losing because the traps he set up for the other racers backfired on him. After Wacky Races, Dastardly and Muttley got their own show titled Dastardly and Muttley in Their Flying Machines, which revolved around their attempts to catch Yankee Doodle Pigeon and prevent him from delivering messages to the enemy side. Similarly to Wacky Races, Dastardly's intricate traps always backfired on him, causing the Pigeon to flee from his reach.
More than 50 years later, it seems like the near-impossible quest to catch the elusive bird is a thing of the past. One of the many Hanna-Barbera easter eggs in Scoob shows a stuffed pigeon lying on the shrine Dastardly constructed for the missing Muttley when the villain explains to Daphne (Amanda Seyfried), Velma (Gina Rodriguez), and Fred (Zac Efron) how he lost the dog. The figure has the exact same blue helmet, goggles, and red kerchief as the original Yankee Doodle.
This makes sense within the context of the movie. Most of the differences between Scoob! and the original cartoon stem from the fact that the film aimed to create a shared Hanna-Barbera universe where the characters have progressed past their original adventures. The Mystery Inc. gang is tackling a supervillain instead of a regular low-scale mystery, the original Blue Falcon has retired, and even the Mystery Machine gets a high-tech update at the end of the film. It only makes sense for the movie's main villain to go from chasing a speedy pigeon to attempting to unleash the dog-pocalypse.
With such a drastic modernization of the franchise, some things in Scoob were bound to make no sense. Details like Scooby's ancient heritage, the three Cerberus skulls, and Dick Dastardly's portal to the underworld might test the audience's suspension of disbelief. But other little details like the stuffed Yankee Doodle Pigeon in Dick Dastardly's Muttley shrine prove that Scoob's ambition of a shared Hanna-Barbera cinematic universe can truly have more depth than it gets credit for.