Kabumpo in Oz. One of the follow up Oz books. The series was continued by Ruth Plumley Thompson, as I remember. It was started by L. Frank Baum, and it included The Land of Oz and The Wizard of Oz. I guess we all know about the Wizard.
Kabumpo was an elephant...a talking elephant. He and the Prince of a suburb of Oz set off so the Prince can marry Ozma, the princess of Oz who lives in the Emerald City. Grandfather used to read a chapter a night as a bed time story. I loved it and the characters and especially the sardonic elephant. When I was old enough to read a book by myself, I reread it... and then again and again.
"Oh, my purple socks and soup spoons," cries one of the characters who is wronged by the villian, Ruggedo, the Red, who lives underground, right under the palace of the Emerald City.
See, I remember it still. That is the sign of a good children's book.
Later I read other Oz books, The Cowardly Lion, and one featuring Notta Bit More a circus clown. I also read the Baum Oz books. The Baum books were more literary, filled with adult references and parodies, while the Thompson books were mere narratives. If there was any social commentary, I didn't see it.
I think they all need a reread, now that I am eighty two.