It's Raining Bats and Frogs by Rebecca Colby. Published by Scholastic.
I based this song on the old Rain, Rain go Away song, but changed it some. Each time it's in the book, the words change and so I put the music in twice to show how to add the extra words. I didn't add instruments because I will probably use it in October, and I like for my students to improvise an accompaniment. I put it in C, but it might be easier with Orff instruments to put it in d minor.