My mother sang this to me as a child, A little differenty but here is how she sang it:

The moon shone bright on a saturday night,
and the bar was closed for the night,
when out of the corner crept a little old mouse,
who danced in the pale moonlight,
he lapped up the liquor on the bar room floor,
and back on his tail he sat,
and all throght the night you can hear him yell
Bring on the dog gone cat!!