Ackshuly, I have heard the line as interpolated as "Bad moon in the night," which almost makes sense. In the second place, I have have also heard the "Swell Fwoop" as another mangling of "Fell Swoop."
Nice interpretation of "Spit and Image."

Not too long ago, I heard that asparagus derived from "Sparrow Grass." I don't know whether it is true or not.