Hans Neuenfels’s Bayreuth Festival Lohengrin has become an improbably beloved production. Klaus Florian Vogt’s Lohengrin is justifiably the most popular performance of the festival and the score sounds amazing in the space, even though it predated the Festspielhaus. But the production: famous for its chorus of rats, it seemed like the kind of thing that would be remembered for one weird image, put into a collective Strange Opera photo album along with Neuenfels’s Nabucco with bees and that Bieito Ballo that no one can get over. Instead it became an almost instant classic. In part it is memorable for the rats’ indexicality, yet the rats are not only an image but a compelling idea. And while the rats would seem to preclude the romantic knight in shining armor aspect of this opera, that’s not really what happens.