Scientific name: necronomicon lorelength
Elementality: vitality, aqua.
Diet: souls, mana, insects, mold
Conservation status: extinct in wild
Can be kept as pet?: NO. not only will it probably kill you, but the license to handle one is nearly unfathomably expensive unless you've been assigned one by royalty.
Notes: YES, THE NAME'S CONFUSING. WE NAMED IT BEFORE WE SEPARATED WYRMS AND AMPHIPTERE.
Extinct in the wild due to elves exterminating full libraries of them, very few remaining forbidden bookworms are used to guard written texts that must be preserved, but not read unless TRULY DIRE circumstances are in effect. This includes the actual necronomicon, most known scrolls of terasque summoning, divine favors, the book of universal knowledge, the book of the dead, wish scrolls, and, perhaps most importantly, an entire library filled with maginuclear trapped wizard spell books.
If you ever wondered why you're not allowed to fill an entire book with glyphs of wardring fireball, THAT LIBRARY IS WHY. They're so charged we can't destroy them, if we tried, it could take out a city. WE HAVE ONE BUILDING FILLED WITH THREE THOUSAND OF THEM. We have filled that library with the entire remaining population of forbidden bookworms. That is their entire habitat now.
With the exception of other forbidden bookworms in differing locations. My forbidden bookworm guards the dragon tome, and my kingdom's tax documents. It has killed nine people so far.
I'm not telling you how it kills you, because it is very important to the continued existence of the world that they can catch you by surprise.