We used to sing this in puplic school in 1968 when I was in grade 3. It was in our class song books.   ...one of my favs as a kid.

After a few minutes of google I was finally able to find the words on someones blog in Europe.

"Hallowee-ee-een there are witches flying by.
Have you see-ee-een their shadows in the sky?
So beware don't you dare,
Give a boast or a ghost
Might come and pull your hair!"

There ya go!