Eye of Nept

Cannot be auctioned, traded, bazaared, or delivered.
Cannot be obtained as a random reward from the Gobbie Mystery Box Special Dial and similar sources.

Each of the Item-slot items dropped by the Avatars which are used in the Mama Mia quest were a Key Item from one of the first seven Final Fantasy games. Eye of Nept (called Eye in the original unofficial English translation) was a key item in Final Fantasy III, which was used to restore the statue of Nepto in Nepto's Shrine to its original splendor. This had the effect of calming the sea serpent Nepto, bringing him out of his savage, berserk state and allowing the sea on the Floating Continent to be safe to travel.