Ephraim Kishon wrote a satire like that about his editor asking him to write a children's book featuring some animal, because that's the only way to still make money writing books.

There is some brainstorming on which animal to use, but it invariably turns out that the animal in question had already been taken, always featuring in some repetitive plot along the lines of "animal child runs away from home (possibly by travelling on a jeep), experiences various adventures and eventually returns back home". Eventually they hit upon the idea of writing something about a deep-sea sponge, which turns out to have not been taken by anybody else so far.

The first volume of the new series of books is "David The Deep-Sea Sponge Goes To Town" [1], where David breaks free from his parental home in order to pursue a career as a bath sponge in Jerusalem. In the volume after that, he'll return home again – most likely on a jeep.

[1] Freely translating from the German version here, where most animals have alliterative names. No idea if that story ever had an official English translation and what the sponge might have been called there.