Gabby-Two for the Zoo (1941)

Gabby and the head zookeeper at the Lilliput Zoo bring in a new kangaroo to the zoo. A delivery man pushes a crate down the street containing a Rubber Necked Kango. Gabby bumps into the crate, and in his usual know-it-all fashion, offers to personally deliver the animal, a baby. Gabby doesn't know that the mother is also in the crate, and she catches up with them, dropping the baby into her pouch, causing Gabby to think that the baby suddenly grew. They end up getting trapped in the kangaroo's cage and the Kangaroo runs free.