Piranha 3D opened over the weekend, and, for those who didn’t see it (me, for instance), it did reasonably well—a 74 percent rating on Rotten Tomatoes, and $18.3 million at the box office. Not spectacular, but enough to ensure the movie will earn back its modest $24 million budget. Among the movie’s fans, however, you will not find James Cameron, who trashed the movie as “an example of what we should not be doing in 3D” and added, “It just cheapens the medium and reminds you of the bad 3D horror films from the 1970s and 80s, like Friday the 13th 3D.” (The fact that Mr. Cameron was fired as director of Piranha 2 is utterly irrelevant to this discussion, and shame on you and your cynicism.) But Cameron badly underestimated his opponent, just like Quarritch and those blue Thundercats. Piranha 3D producer Mark Canton responded with a 1400-word email that has to be read in its entirety to be believed. From the first paragraph:

Mr. Cameron, who singles himself out to be a visionary of movie-making, seems to have a small vision regarding any motion pictures that are not his own. It is amazing that in the movie-making process – which is certainly a team sport – that Cameron consistently celebrates himself out as though he is a team of one. His comments are ridiculous, self-serving and insulting to those of us who are not caught up in serving his ego and his rhetoric.

Lots more good stuff, reaching a peak with Canton’s observation: “Not everyone has the advantage of having endless amounts of money to play in their sandbox and to take ten years using other people’s money to make and market a film….like you do.” Cameron, who has rarely been accused of being a nice or gracious guy, probably won’t have the sense to walk away from this fight. But it’s starting to look as if that might be the smart thing to do.