Bell used by worshippers of revenants. Ring bell, using FP to summon prowling wraiths. This can be done multiple times in a row. Wraiths are said to be the vengeful spirits of those who died when cursed.

Where to Find the Wraith Calling Bell

Found down some stairs in the Laskyar Ruins in Liurnia of the Lakes — see Central section of walkthrough for details on acquiring.