Summon your aurelia polyp minion. Lighter than air─er...water.
Hitching a ride in the ballast tank of a submersible proved an enlightening experience for this infant wavekin, allowing it to listen in on the incessant mumblings of the vessel's pilot─a mammet voyager tasked with taking an audio log of all discoveries made.
How to obtain:
Voyages -- Subaquatic Voyages - Deep-sea Site (E/G/K/S/U/AA), Sea of Ash (S), Sea of Jade (C), Sirensong Sea (I)
Bozja -- Southern Front Lockbox / Zadnor Lockbox
Occult Crescent -- South Horn - Bronze/Silver Coffer