Bilbiophages are a snake-like Nithling. They spit a type of venom that reduces any kind of writing to Nothing. They are attracted to writing, be it a sentence or a letter, which they then try to destroy. The Will was extremely shocked with the creation of this Nithlings, as it also means The Will would be uncapable of passing the threshold. It is a defence set by Mister Monday because the Will couldn’t get past to the Dayroom to interfere. As shown in Mister Monday , within seconds of coming into contact with any type of writing, they dissolve it back to Nothing.