Fantasma di Maomao (famiglio)s are the ghosts of pets which have died. The pet either died due to negligence on the owner's part (see Keeping Your Pet Alive) or was put down on purpose by a Butcher in order to provide food for a Pink Dragoone. A pet killed by a butcher loses all the statistic bonuses it had gained from feeding. This makes them stackable in one's inventory, so that several butchered bow meows, for example, occupy only one item slot.
Fantasma di Maomao (famiglio)s can be brought to life again in several ways. Firstly by completing the Pet Cemetery Dungeon (And recieving a Resurrection Powder, by obtaining a Resurrection Powder (By buying, or due to rollback etc.) then taking them to Doro L. Blak in the The Temple of Xelor. Butchered pets will not recover lost stat points.