The Secret Six debut in "Homeward Hound", an episode of What's New Scooby-Doo? They are a litter of Golden Retriever puppies owned by Mr. B; their mother is Crissie.
The puppies' names are Bling-Bling, Maize, 14-Karat, Jingle, Flax and Knox.
The puppies were stolen by Scar and Skull, henchmen of Meadow, at a dog show, but were brought back by Scooby-Doo, whom Scar and Skull also dognapped. Meadow wanted the Secret Six out of the way so her own dog wouldn't have to compete with them.
The puppies returned in the third-season episodes "Farmed & Dangerous" and "Gold Paw".
- The name might be based on Enid Blyton's Secret Seven.
- Although they cannot properly talk, in "Homeward Hound", the puppies revealed potential by managing to say "Doo" at the end, along with Scooby's sign-off.
- It's unknown who the father is, but he is most likely a Golden Retriever like Crissie.