A crooked man walks a crooked mile and gathers a crooked household to match, right down to the crooked cat and mouse. The repeated word is the whole game, and children love supplying it.
From Mother Goose / Nursery Rhymes (traditional). See the whole collection.
There was a crooked man, and he went a crooked mile,
He found a crooked sixpence beside a crooked stile;
He bought a crooked cat, which caught a crooked mouse,
And they all lived together in a little crooked house.
About this rhyme
A crooked man walks a crooked mile, finds a crooked sixpence, and buys a crooked cat that catches a crooked mouse, then they all live together in a little crooked house. Every single thing in it is crooked, which is the whole joke, and children tend to notice that for themselves. Best said building up speed as the list goes on.
Public domain. Text from The Real Mother Goose (Blanche Fisher Wright, 1916), via Project Gutenberg. View the source edition