From the Super Mario Wiki, the Mario encyclopedia
Hammer Island is a location in Paper Mario: The Origami King, an island located in The Great Sea. It is found in the west part of the sea, charted in territory A-4 and indicated by a hammer icon on the map. Notably, the Legendary Hammer, the strongest hammer in the game, is found here. There are no Not-Bottomless Holes to be found here.
Upon arriving at the island, Captain T. Ode notes its shape and names it accordingly. At the time Mario and Olivia get off the boat and onto the dock, it appears the island is peaceful, with not much more than a treasure chest in the middle and a statue in back. The statue reads "Seek ye a path to paradise", while the treasure chest contains the Legendary Hammer, described as the strongest hammer in the game. Opening the chest reveals half a dozen Fire Bros which throw fireballs to light Mario's path on fire. Mario must get onto the adjacent areas and defeat the Fire Bros to clear the path, revealing three small holes in the ground. One contains a good number of 10-Coins, one contains a Shiny Mushroom, and the other contains one Toad in the form of a red scroll. As thanks for rescuing him, he indicates an area on the map for diving. This is Hammer Island's only Toad.
Likewise, there are only two Collectible Treasures to be found here, each on the left side of the island. Collectible Treasure #78: Hammer is simply found in a treasure chest. There is a pile of luggage nearby consisting of a barrel, a crate, a net, and some rope. Mario must jump while on the crate to reveal a Hidden Block containing Collectible Treasure #79: Captain T. Ode. Notably, all of the other ? Blocks on this island are found as Hidden Blocks as well.
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