If that was my server I would of course put a joke in /etc/shadow - did you try to brute force the hashes? It would not be a great surprise to find some obvious funny content if you try?
That's a pretty long passphrase, so someone would have to have put it in the word list directly to ever guess something that long. Would be fun though.
Like for example, if the entry for root in the joke /etc/shadow was the hash of "Thank you Mario! But our princess is in another castle!"