And, incidentally, I agree with Bev & Jerry, the original needs to be well known to the audience. But it's a lot easier if it's very well known to the parodist, else it's not likely to work.

"Imitation is the sincerest form of flattery.", I've yet to decide whether this also applies to parody, but I feel it's true that you can't do justice to a song in parody unless the origanal can be called easily to mind while working.

Nigel