Setting all that aside, here's a post on the topic of pseudofilks, or cryptofilks, or whatever you want to call these things...
Often, when writing a song parody, I'll keep a line from the original song intact. Sometimes, that line motivated the parody in the first place. Other times, it comes as a surprise, even to me. Usually, the context of the filk changes the meaning of the line in a way that's particularly ironic, poignant, or otherwise powerful or punchliney. I mentioned a number of these at a song-parody-writing panel at Arisia.
And then there are the songs where, once I realize the twist that makes the parody work, the region of lyrics that can be kept, albeit with a changed meaning, grows and grows until it swallows the whole song. All the lyrics exactly the same. Then what? How do you perform such a filk — what establishes the context that changes the meaning, that makes the difference between the filk and the original song? These oddities are what I'm calling "pseudofilks".
The possibility of having a beloved song ruined for you forever minor, implicit spoilers for Babylon 5, and major spoilers for A Fire Upon the Deep follow ( after the cut )