Pokénomicon (book)

A Pokénomicon is a tome of elder lore that contains information about thulhu that a cultist has encountered. Most cultists construct their Pokénomicons themselves, but even those who receive them as gifts must have the books bound to them at a Stone Circle when the stars are right. Pokenomicons have lots of pages, and can (using strange geometries bestowed on them in the binding ritual) grow more pages when necessary. The book acts as a kind of maxi-grimoire that lets its owner quickly summon bound thulhu from the dodecahedrons they're stored in. While cultists can (and often do) write in the books themselves, the pages magically fill themselves in with details about thulhu as the cultists discover them. These writings are written in a special script that can only be read by the proper owner.