The Monsters of Bob

There are monsters on the land of Bob.
Some are hairy and scary, with long spikes down their back.
Others are small and quick, with nimble fingers that have eyes at each tip.
So what do the monsters do to pass each day?
Why, they sing songs made up of the unique sound each monster makes.
For in the land of Bob, each monster can make only one sound.
A growl or a hiss, a yowl or a groan.
Only the one sound, the sound that's their own.
But each Tuesday night, at just after eight o'three, the monsters all gather for a song jamboree.
They take their sound, and the make out loud.
Growl!
Roar!
Hiss!
Snarl!
Their sounds mingle together, and cause such a fright!
That none of the neighboring villages get any sleep on Tuesday nights!