My version, remembered from my Dad who used to sing it in the 60s and 70s goes

Hush little baby don't say a word
Mamas gonna buy you a mocking bird
And if that mocking bird don't sing
Mamas gonna buy you a diamond ring
And if that diamond ring turns brass
Mamas gonna buy you a looking glass
ANd if that looking glass turns cloudy
Mamas gonna buy you a horse and buggy
And if that horse and buggy turns over
Mamas gonna buy you a dog named rover