https://www.amazon.com/dp/B08HWP35TY
It takes place on Earth after all life has ended and been replaced by ghosts. One day, a single ghost sees a bizarre being what must be the first living thing centuries. Will she be able to convince others of her wondrous discovery? How has no one else seen one? Is it connected to the recent disappearances of other ghosts?
If nothing else, this book has probably the widest variety of ghosts I've ever seen in a book, with a number of inspired designs. Bogleech illustrated some of them here:
https://bogleech.com/halloween/hall20-rotl.html