I vaguely recall the Herr Wozzeck one you mentioned. (Was the Gdoc one not it?) Other than that, though, I don't think it's happened very often at all. As far as I know, it's rare for an author to find out we sporked them, and rarer still for them to say anything about it, let alone go to the effort of writing a whole nother fic just to have a go at us.

But, if someone does want to write a revenge fic, we can't stop them. They're as free to write a response to our stuff as we are to write a sporking of theirs. We don't have to like it, but we also don't have to have a fit about it. If it's entertaining, we should laugh. If it has a point, we should listen. If it's nasty enough to violate the TOS of the archive it's on, we should report it. If it isn't any of those things, we should ignore it.

Then we should move on. Simple as that.

~Neshomeh

It was written by myself, with my own character - that's not revenge fic, that's an agent having a very bad day. (Plus or minus fifteen years of growing as a writer. You know how it is.)