Hush Little Baby Song

The transcript describes a series of gifts a father promises to buy for his child if each previous gift fails to meet expectations. Starting with a mockingbird, the sequence includes a diamond ring, looking glass, billy goat, cart and ball, dog named Rover, and a horse and cart. Despite any failures, the child remains the sweetest baby in town.

What will Papa buy if the dog named Drover won't bark?

What is the final promise Papa makes if the horse and cart falls down?