''Lovecraftian Monsters'' Category shows in the category list but it will not add as a category.

It has zero entries but it does show on the list. It shows the alpha sort bar

It doesn't show on the edit category 'add category' pulldown

If added manually as a category using source edit, it shows on the page as a page that does not exist

I know of at least 4 monster pages that are Lovecraftian Monsters

Cthulhu, mrs pickman, sutter kane and kane's madness plus, there areprobably more.