The mystery entry turned out to be a copy of The God Delusion. Excerpt follows:
The post on Pharyngula is only 1/2 hour old, but there are already 150+ comments. If PZ was looking to send a message, I'd say he succeeded.
I know some of you have proposed intricate plans for how to do horrible things to these crackers, but I repeat…it's just a cracker. I wasn't going to make any major investment of time, money, or effort in treating these dabs of unpleasantness as they deserve, because all they deserve is casual disposal. However, inspired by an old woodcut of Jews stabbing the host, I thought of a simple, quick thing to do: I pierced it with a rusty nail (I hope Jesus's tetanus shots are up to date). And then I simply threw it in the trash, followed by the classic, decorative items of trash cans everywhere, old coffeegrounds and a banana peel. My apologies to those who hoped for more, but the worst I can do is show my unconcerned contempt.
By the way, I didn't want to single out just the cracker, so I nailed it to a few ripped-out pages from the Qur'an and The God Delusion. They are just paper. Nothing must be held sacred. Question everything. God is not great, Jesus is not your lord, you are not disciples of any charismatic prophet. You are all human beings who must make your way through your life by thinking and learning, and you have the job of advancing humanities' knowledge by winnowing out the errors of past generations and finding deeper understanding of reality. You will not find wisdom in rituals and sacraments and dogma, which build only self-satisfied ignorance, but you can find truth by looking at your world with fresh eyes and a questioning mind.