Here's the definitive version:

Be kind to your web-footed friends
For a duck may be somebody's mother
Be kind to your friends in the swamp
Where the water is very damp (rhymes with swamp)

Be kind to the camel in the zoo
For his hump may be hiding your brother
Be kind to the tiger and the monk
And we will let you smell our favorite: The skunk!

Be kind to the monster mash, the monster mash!
Won't you be so kind to the purple people eater, purple people eater
Won't you be so kind to all the people who come here from outer spaces
Won't you be so kind to all your shoesies and to all your shoesies' laces
Won't you be so kind when teacher thanks you
Won't you be so kind when Daddy spanks you
Won't you be so kind, so kind, so kind, so kind, so kind, so kind, so kind… SO KIND!



*On the 3rd iteration, you can either end with "SO KIND!" or you can sing the first verse one last time (the one ending with "Where the water is very damp" and then sing:

You may think that this is the end
Well, it is! (Abrupt ending)