The Ultra Hammer is an item that made its first appearance in Super Mario RPG: Legend of the Seven Stars. It could be obtained after finding it in a chest in the Factory area. It is considered to be the second strongest weapon for Mario in the game.
It would appear in Paper Mario and Paper Mario: The Thousand-Year Door as the strongest variation of the Hammer. It can deal six damage of health to an enemy when it isn't uncharged and can break all types of blocks.
The Ultra Hammer would also be the last Hammer in Mario & Luigi: Superstar Saga to obtain. It can break the black rocks in the field.