...I wouldn't necessarily call this a badfic. Yeah, it's in script format, but it's honestly not terrible enough to be a badfic, in my opinion.

Gilbert and Sullivan operettas are silly and utterly ridiculous by their very nature as lampooning British society in the late 19th Century. Thus, they rely on all sorts of ridiculous plot devices; think up of any contrivance in fiction, and G&S probably used it for laughs in at least one of their operettas, if not more than that. Really, things adhering to some sense of logic is a big no-no in a G&S operetta, as Anna Russel hilariously shows off in her parody videos on how to write a G&S operetta:

http://www.youtube.com/watch?v=Yif-5xBbxd4
http://www.youtube.com/watch?v=x59vFkATXR4&feature=related

The crossover itself being utterly ridiculous comes with the territory, really.

And really, when we take into account the G&S aesthetic, this guy mostly gets it right. Some of the rhythm can get a little awkward at times and the stresses in some of the lines of the patter song tend to fall on the wrong beats, but the rhymes are extremely inventive and the content of the libretto falls perfectly into that over the top W.S. Gilbert manner that they need to.

So honestly, it's not that bad, and I probably wouldn't spork it.