One Piece (1999)

S01E18 You're the Weird Creature! Gaimon and His Strange Friends!

Now that Usopp has officially joined the crew and they have the Going Merry as their ship, the Straw Hats set sail for an island rumored to conceal a legendary treasure. However, their adventure takes an unexpected turn when they stumble upon a peculiar man trapped inside a treasure chest, who is also in pursuit of the very same treasure.