Aside from the pet crab, you might get some Roblox Islands items like the Pirate Chandelier, Puffer Fish, Pirate Ship or even a Shark. Each chest that you open gives you a random shot at a prize.

After completing this quest, you can move on to the next island in the First Sea and continue to work towards your goal of becoming a Swashbuckling Pirate in Roblox Blox Fruits.