Also, I really like the 3e Nerra just because it's so cool to see something based on one of the more obscure monsters out there, in this case Borges' "Fish in the Mirror"

Also, speaking of Borges, did you know that the Peryton was not from actual Greek myth, but was likely invented by Borges? Its first recorded appearance was in Borges' "Book of Imaginary Beings," and while he talks about getting his information on it from several different sources, note that all those sources seem to have "mysteriously" vanished or been destroyed. And if you know anything about Borges, you know he loved describing works of fiction that didn't exist...