I downloaded the snapshot but when I go and open a book and quill, the tan background is gone, instead is just a white box but I can still type in it. I tried re installing it but I still have the problem. Can someone help?
That's just the block name used for Silverfish hiding in blocks within the stronghold. If you give yourself 97 (the block's ID), the tooltip will say Stone Monster Egg to signify that it's basically a stone block with a monster (Silverfish) inside.