A nonsense counting-out rhyme, the kind chanted while pointing round a circle of children to choose who's 'it'. The invented words, 'muskidun', 'twiddle 'em, twaddle 'em', are pure fun to say.
From Mother Goose / Nursery Rhymes (traditional). See the whole collection.
Hickery, dickery, 6 and 7,
Alabone, Crackabone, 10 and 11,
Spin, spun, muskidun,
Twiddle 'em, twaddle 'em, 21.
Public domain. Text from The Real Mother Goose (Blanche Fisher Wright, 1916), via Project Gutenberg. View the source edition