Sir William Wexell Wingding Whizzlebang the Third (also known as Wiggy Jiggy Jed) was Billy's dog for one episode Dream Mutt. He was originally four different dogs that were used in a game show Billy entered because he wanted a dog, Harold (his dad) wanted him to only have one but Billy wanted them all so he decided to use Grim's scythe to combine them the end result was a talking Hanna-Barbera like dog with a Confederate cap that floated above his head, a black tie, and spoke like Yogi Bear.
He mostly spoke in rhyme and loved disgusting things like telling Billy he like cockroaches and vomit and he often told jokes with a laugh track and he signaled to the audience when he wanted them to stop, but eventually their friendship came to an end when Billy didn't want him to sleep in his bed and made him sleep outside. He eventually began a plan using a giant robot to steal every bed in town so he'll have a new place to sleep every night. Billy, Mandy, and Grim decide to stop him by using a magic gelatin that dissolves him leaving only his hat and tie behind which Billy took.
In the episode Keeper of the Reaper, Mandy brings up Jed because of how badly Billy treated him, and Billy defended himself by saying he grew bored of him. His hat is used as evidence, which Fred Fredburger interrupts the court to try on.
- All four dogs that Jed was created from are female dogs, while Jed himself is shown to be a male dog.
- Wiggy Jiggy Jed appears to be a spoof of Hanna Barbera's anthropomorphic dog characters such as Huckleberry Hound, Augie Doggie and Doggie Daddy, and Hokey Wolf.