The Two Jays of Dribblepit: Book 4. A Dog, a Cat, and a Wizard at Stinky Bottom

Shulfi takes Jem and Jeminee for a walk — please note HE TAKES THEM, not the other way round!
Down Wishonacloud Lane to the path beside Stinky Bottom, Shulfi pulls the Two Jays. On the beach at Puddleowater the kids meet the extraordinary Picture Wizard. She knows all about them and where Shulfi came from and teaches them how to control him. Or does she?
Shulfi takes off on a whim and flutle won’t stop him and the Jays can’t keep up. Disaster strikes when they find him drowning in the muddy bog of Stinky Bottom with something in his mouth.
Shulfi drags himself and his little prize onto the Crag. The two inventive humanoids come up with a clever plan, get covered in disgusting mud, and make mudslippers to rescue Shulfi and his little friend, Dingbat, and then make it home in time to be hosed down again by Jeminee’s mum, Sandy.