The legendary shellshocker has appeared, and Autumnia is under threat! Time to deal with this torrid turtle once and for all!
This bounty is available to complete after completing the main story.
Your target is east of Hamelin, so Travel there, then hop on Tengri. Fly over the mountains to the east and drop your party off on the path leading up to the mine near the edge of the ocean; the Shellshocker will be walking up and down the path here. He's not weak to anything, so buff up your strongest familiars is you can, then let loose. If by chance he decides to boost his Magic Defense with Bracer, then switch to your stronger magical familiars or Oliver himself and barrage him with spells.
Defeat it and you'll complete the bounty hunt, return to the Swift Solutions to claim your reward.