Well, Joe Bethancourt says he first heard it in the early '70s, and that it was introduced to "Madison area pagans" about that time, but he doesn't say where he thinks it comes from. I know filkers who claim to have heard it in the early '60s, but that was way before my time, so I can't vouch for it.

Most filkers know several verses, and the song can go on in a filk circle for what seems like hours, given enough people.

In any case, its a fairly obvious parody, so I don't doubt that versions cropped up all over the place, independently.

Jim.